Is cineál carraige bruitíneach é eibhear a bhaintear as a neart, a dhlús, a marthanacht agus a fhriotaíocht i gcoinne creimeadh. Ach tá eibhear an-ildánach freisin - ní hamháin le haghaidh cearnóga agus dronuilleoga atá sé! Déanta na fírinne, oibrímid go muiníneach le comhpháirteanna eibhir atá innealtóireachta i gcruthanna, uillinneacha agus cuartha de gach cineál go rialta - le torthaí den scoth.
Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:
■ inmheaisínithe
■ cothrom go beacht nuair a ghearrtar agus a chríochnaítear é
■ frithsheasmhach in aghaidh meirge
■ buan
■ buan
Tá comhpháirteanna eibhir éasca le glanadh freisin. Agus dearaí saincheaptha á gcruthú agat, bí cinnte eibhir a roghnú mar gheall ar a buntáistí sármhaithe.

CAIGHDEÁIN / FEIDHMEANNA ARDCHAITHEAMH
Tá cion ard grianchloch sa ghloine a úsáideann ZHHIMG dár dtáirgí pláta dromchla caighdeánach, rud a sholáthraíonn friotaíocht níos fearr i gcoinne caitheamh agus damáiste. Tá rátaí ísle ionsúcháin uisce ag ár ndathanna Superior Black, rud a laghdaíonn an fhéidearthacht go meirgefaidh do thomhasairí beachtais agus iad á socrú ar na plátaí. Mar thoradh ar na dathanna eibhir a thairgeann ZHHIMG, bíonn níos lú glare ann, rud a chiallaíonn níos lú brú súl do dhaoine aonair a úsáideann na plátaí. Roghnaíomar ár gcineálacha eibhir agus leathnú teirmeach á chur san áireamh againn d’fhonn an ghné seo a choinneáil íosta.

CUSTOM APPLICATIONS
Nuair a bhíonn pláta le cruthanna saincheaptha, iontrálacha snáithithe, sliotáin nó meaisínithe eile ag teastáil le haghaidh d’fheidhmchláir, ba mhaith leat ábhar cosúil le Black Jinan Black a roghnú. Cuireann an t-ábhar nádúrtha seo dolúbthacht níos fearr, maolú creathadh den scoth, agus inmheaisínteacht fheabhsaithe ar fáil.

Tá sé tábhachtach a thabhairt faoi deara nach léiriú ar cháilíochtaí fisiciúla na cloiche é an dath amháin. Go ginearálta, baineann dath eibhir go díreach le láithreacht nó neamhláithreacht mianraí, agus ní fhéadfadh aon tionchar a bheith aige sin ar na cáilíochtaí a dhéanann ábhar maith pláta dromchla. Tá eibhir bándearg, liath agus dubh ann atá den scoth le haghaidh plátaí dromchla, chomh maith le heibhir dubh, liath agus bándearg atá go hiomlán neamhoiriúnach d'fheidhmchláir bheachtais. Níl baint ar bith ag tréithe criticiúla eibhir, a bhaineann lena úsáid mar ábhar pláta dromchla, le dath, agus is iad seo a leanas iad:
■ Dolúbthacht (diall faoi ualach - léirithe ag Modúl Leaisteachta)
■ Cruas
■ Dlús
■ Friotaíocht chaitheamh
■ Cobhsaíocht
■ Poróiseacht

Rinneamar tástáil ar go leor ábhar eibhir agus rinneamar comparáid idir na hábhair seo. Ar deireadh, fuair muid an toradh, is é eibhear dubh Jinan an t-ábhar is fearr a bhfuil aithne againn air riamh. Tá eibhear dubh Indiach agus eibhear na hAfraice Theas cosúil le Eibhear Dubh Jinan, ach tá a n-airíonna fisiceacha níos lú ná Eibhear Dubh Jinan. Leanfaidh ZHHIMG ag cuardach níos mó ábhar eibhir ar domhan agus déanfaidh siad comparáid idir a n-airíonna fisiceacha.

Chun tuilleadh eolais a fháil faoin eibhear atá ceart do do thionscadal, déan teagmháil linninfo@zhhimg.com.

Úsáideann monaróirí éagsúla caighdeáin éagsúla. Tá go leor caighdeán ar fud an domhain.
Caighdeán DIN, ASME B89.3.7-2013 nó Sonraíocht Chónaidhme GGG-P-463c (Plátaí Dromchla Eibhir) agus mar sin de mar bhonn dá sonraíochtaí.

Agus is féidir linn pláta cigireachta cruinneas eibhir a mhonarú de réir do riachtanais. Fáilte romhat teagmháil a dhéanamh linn más mian leat tuilleadh eolais a fháil faoi chaighdeáin eile.

Is féidir cothromaíocht a mheas mar gach pointe ar an dromchla atá suite laistigh de dhá phlána comhthreomhara, an plána bonn agus plána an dín. Is é tomhas an achair idir na plánaí cothromaíocht fhoriomlán an dromchla. De ghnáth bíonn lamháltas ag baint leis an tomhas cothromaíochta seo agus d'fhéadfadh ainmniú gráid a bheith san áireamh ann.

Mar shampla, sainmhínítear na lamháltais cothromaíochta do thrí ghrád chaighdeánacha sa tsonraíocht chónaidhme mar a chinntear leis an bhfoirmle seo a leanas:
■ Grád Saotharlainne AA = (40 + trasnán cearnógach/25) x .000001" (aontaobhach)
■ Grád Cigireachta A = Grád Saotharlainne AA x 2
■ Seomra Uirlisí Grád B = Saotharlann Grád AA x 4.

I gcás plátaí dromchla de mhéid chaighdeánach, ráthaímid lamháltais chothromais a sháraíonn ceanglais na sonraíochta seo. Chomh maith le cothromas, pléann ASME B89.3.7-2013 & Sonraíocht Chónaidhme GGG-P-463c ábhair lena n-áirítear: cruinneas tomhais athuair, airíonna ábhartha eibhir pláta dromchla, bailchríoch dromchla, suíomh pointe tacaíochta, dolúbthacht, modhanna cigireachta inghlactha, suiteáil iontrálacha snáithithe, etc.

Comhlíonann plátaí dromchla eibhir ZHHIMG agus plátaí cigireachta eibhir na ceanglais uile atá leagtha amach sa tsonraíocht seo, nó sáraíonn siad iad. Faoi láthair, níl aon sonraíocht shainiúil ann do phlátaí uillinne eibhir, comhthreomhar, nó cearnóga máistir.

Agus is féidir leat na foirmlí do chaighdeáin eile a fháil iÍOSLÓDÁIL.

Ar dtús, tá sé tábhachtach an pláta a choinneáil glan. Is gnách gurb é deannach scríobach san aer an fhoinse is mó caitheamh agus cuimilt ar phláta, toisc go mbíonn sé i mbaol dul i bhfeidhm ar phíosaí oibre agus ar dhromchlaí teagmhála na dtomhasairí. Ar an dara dul síos, clúdaigh do phláta chun é a chosaint ar dheannach agus ar dhamáiste. Is féidir saolré an chaitheamh a fhadú tríd an pláta a chlúdach nuair nach bhfuil sé in úsáid, tríd an pláta a rothlú go tréimhsiúil ionas nach bhfaigheann limistéar amháin úsáid iomarcach, agus trí cheapacha teagmhála cruach ar thomhaisairí a athsholáthar le ceapacha cairbíde. Chomh maith leis sin, seachain bia nó deochanna boga a chur ar an pláta. Tabhair faoi deara go bhfuil aigéad carbónach nó fosfarach i go leor deochanna boga, ar féidir leo na mianraí níos boige a thuaslagadh agus poill bheaga a fhágáil sa dromchla.

Braitheann sé seo ar an gcaoi a bhfuil an pláta á úsáid. Más féidir, molaimid an pláta a ghlanadh ag tús an lae (nó an tseal oibre) agus arís ag an deireadh. Má shalachar an pláta, go háirithe le sreabháin olacha nó greamaitheacha, is dócha gur cheart é a ghlanadh láithreach.

Glan an pláta go rialta le glantóir pláta dromchla leachtach nó gan uisce ZHHIMG. Tá an rogha tuaslagán glantacháin tábhachtach. Má úsáidtear tuaslagóir so-ghalaithe (aicéatón, tanaitheoir laicir, alcól, srl.) fuaróidh an galú an dromchla agus saobhfaidh sé é. Sa chás seo, is gá ligean don phláta gnáthú sula n-úsáidtear é nó tarlóidh earráidí tomhais.

Athróidh an méid ama a theastaíonn chun go ngnáthnósóidh an pláta ag brath ar mhéid an phláta, agus ar an méid fuaraithe a dhéantar. Ba chóir go mbeadh uair an chloig leordhóthanach i gcás plátaí níos lú. D’fhéadfadh go mbeadh dhá uair an chloig ag teastáil i gcás plátaí níos mó. Má úsáidtear glantóir uiscebhunaithe, beidh roinnt fuaraithe galúcháin ann freisin.

Coinneoidh an pláta an t-uisce freisin, agus d’fhéadfadh sé seo meirg a chur ar chodanna miotail a bhíonn i dteagmháil leis an dromchla. Fágann roinnt glantóirí iarmhar greamaitheach tar éis dóibh triomú freisin, rud a mheallfaidh deannach san aer, agus a mhéadóidh caitheamh i ndáiríre, seachas é a laghdú.

Braitheann sé seo ar úsáid agus ar an timpeallacht phláta. Molaimid go ndéanfaí athchalabrú iomlán ar phláta nua nó ar ghabhálas eibhir beachtais laistigh de bhliain amháin ón gceannach. Má úsáidtear go mór an pláta dromchla eibhir, b’fhéidir go mbeadh sé inmholta an t-eatramh seo a ghiorrú go sé mhí. Taispeánfaidh cigireacht mhíosúil le haghaidh earráidí tomhais arís agus arís eile ag baint úsáide as leibhéal leictreonach, nó gléas dá samhail, aon spotaí caitheamh atá ag forbairt agus ní thógfaidh sé ach cúpla nóiméad é a dhéanamh. Tar éis torthaí an chéad athchalabrúcháin a chinneadh, féadfar an t-eatramh calabrúcháin a shíneadh nó a ghiorrú de réir mar a cheadaítear nó a cheanglaítear le do chóras cáilíochta inmheánach.

Is féidir linn seirbhís a thairiscint chun cabhrú leat do phláta dromchla eibhir a iniúchadh agus a chalabrú.

Tá roinnt cúiseanna féideartha ann le héagsúlachtaí idir calabrúcháin:

• Níodh an dromchla le tuaslagán te nó fuar roimh an gcalabrúchán, agus níor tugadh dóthain ama dó chun gnáthú.
• Tá an pláta tacaithe go mícheart
• Athrú teochta
• Dréachtaí
• Solas díreach na gréine nó teas radaíochta eile ar dhromchla an phláta. Bí cinnte nach bhfuil an dromchla á théamh ag soilse lastuas.
• Éagsúlachtaí sa ghrádán teochta ingearach idir an geimhreadh agus an samhradh (Más féidir ar chor ar bith, bíodh a fhios agat an teocht ghrádána ingearach tráth a ndéantar an calabrú.)
• Níor tugadh dóthain ama don phláta chun a normalú tar éis loingsithe
• Úsáid mhíchuí trealaimh cigireachta nó úsáid trealaimh neamhchalabraithe
• Athrú dromchla mar thoradh ar chaitheamh

Cé mhéad cineál poill atá ar eibhear beachtais?

Sliotáin ar Chomhpháirteanna Eibhir Beachtas

I gcás go leor monarchana, seomraí cigireachta agus saotharlanna, braitear ar phlátaí dromchla eibhir bheachta mar bhunús le haghaidh tomhas cruinn. Ós rud é go mbraitheann gach tomhas líneach ar dhromchla tagartha cruinn as a nglactar na toisí deiridh, soláthraíonn plátaí dromchla an plána tagartha is fearr le haghaidh cigireachta agus leagan amach oibre roimh mheaisínithe. Is boinn idéalacha iad freisin chun tomhais airde a dhéanamh agus dromchlaí a thomhas. Ina theannta sin, a bhuíochas dá leibhéal ard cothromaíochta, cobhsaíochta, cáilíochta foriomlán agus ceardaíochta, is rogha mhaith iad chun córais tomhais mheicniúla, leictreonacha agus optúla sofaisticiúla a shuiteáil. Maidir le haon cheann de na próisis tomhais seo, tá sé ríthábhachtach plátaí dromchla a choinneáil calabraithe.

Repeat Measurements and Flatness

Tá an chothrom agus na tomhais athuair ríthábhachtach chun dromchla beacht a chinntiú. Is féidir cothrom a mheas mar gach pointe ar an dromchla atá suite laistigh de dhá phlána comhthreomhara, an plána bonn agus plána an dín. Is é tomhas an achair idir na plánaí cothrom iomlán an dromchla. De ghnáth bíonn lamháltas ag baint leis an tomhas cothrom seo agus féadfaidh sé ainmniú gráid a áireamh.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:

Caighdeán DIN, Caighdeán GB, Caighdeán ASME, caighdeán JJS ... tír dhifriúil le seasamh difriúil ...

Tuilleadh sonraí faoin gcaighdeán.

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

Chun a chinntiú go gcomhlíonann pláta dromchla na sonraíochtaí cothromaíochta agus tomhais athdhéanta araon, ba cheart do mhonaróirí plátaí dromchla eibhir Sonraíocht Chónaidhme GGG-P-463c a úsáid mar bhonn dá sonraíochtaí. Pléann an caighdeán seo cruinneas tomhais athdhéanta, airíonna ábhartha pláta dromchla eibhir, bailchríoch dromchla, suíomh pointe tacaíochta, dolúbthacht, modhanna inghlactha cigireachta agus suiteáil iontrálacha snáithithe.

Checking Plate Accuracy

Trí chúpla treoirlínte simplí a leanúint, ba cheart go mairfeadh infheistíocht i pláta dromchla eibhir ar feadh blianta fada. Ag brath ar úsáid an phláta, timpeallacht na ceardlainne agus an cruinneas atá ag teastáil, athraíonn minicíocht seiceála cruinneas an phláta dromchla. Is riail ghinearálta í go ndéanfaí athchalabrú iomlán ar phláta nua laistigh de bhliain amháin ón gceannach. Má úsáidtear an pláta go minic, moltar an t-eatramh seo a ghiorrú go sé mhí.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations

I gcásanna áirithe, bíonn éagsúlachtaí idir calabrúcháin plátaí dromchla. Uaireanta is féidir le fachtóirí amhail athrú dromchla mar thoradh ar chaitheamh, úsáid mhícheart trealaimh cigireachta nó úsáid trealaimh neamhchalabraithe na héagsúlachtaí seo a mhíniú. Is iad an dá fhachtóir is coitianta, áfach, ná teocht agus tacaíocht.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Extend Plate Life

Laghdóidh roinnt treoirlínte caitheamh ar phláta dromchla eibhir agus, sa deireadh thiar, leathnóidh sé a shaolré.

Ar dtús, tá sé tábhachtach an pláta a choinneáil glan. Is gnách gurb é deannach scríobach san aer an fhoinse is mó caitheamh agus cuimilt ar phláta, toisc go mbíonn sé ag dul i bhfostú i bpíosaí oibre agus i ndromchlaí teagmhála na dtomhasairí.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Rothlaigh an pláta go tréimhsiúil ionas nach mbaintear úsáid iomarcach as limistéar amháin. Chomh maith leis sin, moltar ceapa teagmhála cruach a athsholáthar ar thomhasairí le ceapa cairbíde.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap

Nuair is gá pláta dromchla eibhir a athdhromchlú, smaoinigh ar cheart an tseirbhís seo a dhéanamh ar an láthair nó ag an áis calabrúcháin. Is fearr i gcónaí an pláta a ath-lapáil sa mhonarcha nó in áis tiomnaithe. Mura bhfuil an pláta caite ró-dhona, de ghnáth laistigh de 0.001 orlach den chaoinfhulaingt riachtanach, is féidir é a athdhromchlú ar an láthair. Má tá pláta caite go dtí an pointe go bhfuil sé níos mó ná 0.001 orlach lasmuigh den chaoinfhulaingt, nó má tá poll nó scoilteadh mór ann, ba chóir é a sheoladh chuig an monarcha le haghaidh meilt sula ndéantar ath-lapáil air.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Ba chóir a bheith an-chúramach agus teicneoir calabrúcháin agus athdhromchlaithe ar an láthair á roghnú. Iarr creidiúnú agus fíoraigh go bhfuil calabrú inrianaithe ag an trealamh a úsáidfidh an teicneoir. Is fachtóir tábhachtach é an taithí freisin, toisc go dtógann sé blianta fada foghlaim conas eibhear beacht a lapáil i gceart.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.Q

Checklist for Calibration Variations

1. Níodh an dromchla le tuaslagán te nó fuar roimh an gcalabrú agus níor tugadh dóthain ama dó chun gnáthú.

2. Níl an pláta tacaithe i gceart.

3. Athrú teochta.

4. Dréachtaí.

5. Solas díreach na gréine nó teas radaíochta eile ar dhromchla an phláta. Bí cinnte nach bhfuil soilsiú lastuas ag téamh an dromchla.

6. Éagsúlachtaí sa ghrádán teochta ingearach idir an geimhreadh agus an samhradh. Más féidir ar chor ar bith, bíodh a fhios agat cén teocht ghrádán ingearach atá ann tráth a ndéantar an calabrú.

7. Níor tugadh dóthain ama don phláta chun gnáthú tar éis loingsithe.

8. Mí-úsáid trealaimh cigireachta nó úsáid trealaimh neamhchalabraithe.

9. Athrú dromchla mar thoradh ar chaitheamh.

Tech Tips

• Ós rud é go mbraitheann gach tomhas líneach ar dhromchla tagartha cruinn as a nglactar na toisí deiridh, soláthraíonn plátaí dromchla an plána tagartha is fearr le haghaidh cigireachta oibre agus leagan amach roimh mheaisínithe.
• Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.
• Ba cheart go n-áireofaí seiceálacha rialta le huath-choiliméadair i gclár cigireachta éifeachtach, rud a sholáthraíonn calabrú iarbhír ar an gcothromúlacht fhoriomlán is féidir a rianú síos go dtí an tÚdarás Cigireachta Náisiúnta.

I measc na gcáithníní mianracha atá sa ghreabhán, is feldspar agus grianchloch níos mó ná 90% díobh, agus is é feldspar an chuid is mó díobh. Is minic a bhíonn an feldspar bán, liath agus dearg mar fheoil, agus is grianchloch den chuid is mó gan dath nó bán liath, agus is iad sin bun-dath an ghreabháin. Is mianraí crua iad feldspar agus grianchloch, agus is deacair iad a bhogadh le scian cruach. Maidir leis na spotaí dorcha san ghreabhán, den chuid is mó mica dubh, tá roinnt mianraí eile ann. Cé go bhfuil biotite sách bog, níl a chumas strus a sheasamh lag, agus ag an am céanna tá méid beag acu san ghreabhán, go minic níos lú ná 10%. Is é seo an riocht ábhartha ina bhfuil an ghreabhán thar a bheith láidir.

Cúis eile a bhfuil eibhear láidir ná go bhfuil a cháithníní mianracha ceangailte go docht lena chéile agus leabaithe ina chéile. Is minic nach mbíonn sna póir ach níos lú ná 1% de thoirt iomlán na carraige. Tugann sé seo an cumas don eibhear brúnna láidre a sheasamh agus ní théann taise isteach ann go héasca.

Déantar comhpháirteanna eibhir as cloch gan aon fhriotaíocht meirge, aigéid agus alcaile, friotaíocht mhaith caitheamh agus saolré seirbhíse fada, gan aon chothabháil speisialta. Úsáidtear comhpháirteanna cruinne eibhir den chuid is mó in uirlisí an tionscail innealra. Dá bhrí sin, tugtar comhpháirteanna cruinne eibhir nó comhpháirteanna eibhir orthu. Tá tréithe na gcomhpháirteanna cruinne eibhir mar an gcéanna go bunúsach le tréithe ardáin eibhir. Réamhrá maidir le huirlisí agus tomhas comhpháirteanna cruinne eibhir: Is treoracha forbartha tábhachtacha iad teicneolaíocht meaisínithe beachtais agus micrea-mheaisiú i dtionscal déantúsaíochta innealra, agus tá siad anois ina dtáscaire tábhachtach chun leibhéal ardteicneolaíochta a thomhas. Tá forbairt na teicneolaíochta ceannródaíche agus an tionscal cosanta doscartha ó theicneolaíocht meaisínithe beachtais agus micrea-mheaisiú. Is féidir comhpháirteanna eibhir a shleamhnú go réidh sa tomhas, gan marbhántacht. Tomhas dromchla oibre, ní dhéanann scratches ginearálta difear do chruinneas tomhais. Ní mór comhpháirteanna eibhir a dhearadh agus a tháirgeadh de réir riachtanais an taobh éilimh.

Réimse iarratais:

Mar is eol dúinn go léir, tá níos mó agus níos mó meaisíní agus trealaimh ag roghnú comhpháirteanna eibhir beachtais.

Úsáidtear comhpháirteanna eibhir le haghaidh gluaiseachta dinimiciúla, mótair líneacha, cmm, cnc, meaisín léasair...

fáilte romhat teagmháil a dhéanamh linn le haghaidh tuilleadh eolais.

Tá gléasanna tomhais eibhir agus comhpháirteanna meicniúla eibhir déanta as eibhir dubh Jinan ardchaighdeáin. Mar gheall ar a gcruinneas ard, a marthanacht fhada, a gcobhsaíocht mhaith agus a bhfriotaíocht creimeadh, úsáidtear iad níos mó agus níos mó i gcigireacht táirgí sa tionscal nua-aimseartha agus i réimsí eolaíochta ar nós taighde meicniúil aeraspáis agus taighde eolaíoch.

Buntáistí

----Dhá oiread chomh crua le hiarann ​​teilgthe;

----Is mar gheall ar athruithe teochta is mó athruithe ar thoise;

----Saor ó fháscadh, mar sin níl aon bhriseadh ar an obair;

----Saor ó bhorráin nó ó bhrúiteáin mar gheall ar an struchtúr gráin mhín agus an greamaitheacht neamhshuntasach, rud a chinntíonn an leibhéal ard cothromaíochta thar shaolré seirbhíse fada agus nach ndéanann aon damáiste do chodanna nó d’ionstraimí eile;

---- Oibriú gan trioblóid le húsáid le hábhair mhaighnéadacha;

---- Saol fada agus saor ó mheirge, rud a fhágann costais chothabhála ísle.

Déantar na plátaí dromchla eibhir beachtais a lapáil go beacht go caighdeán ard cothromaíochta chun cruinneas a bhaint amach agus úsáidtear iad mar bhonn le haghaidh córais tomhais mheicniúla, leictreonacha agus optúla sofaisticiúla a shuiteáil.

Seo a leanas cuid de na gnéithe uathúla den phláta dromchla eibhir:

Aonfhoirmeacht i gCruas;

Coinníollacha cruinne faoi ualach;

Ionsúiteach Creathadh;

Éasca le Glanadh;

Frithsheasmhach in aghaidh fillte;

Íseal-thruailliú;

Neamh-Scríobach;

Neamh-mhaighnéadach

Buntáistí Pláta Dromchla Eibhir

First, the rock after a long period of natural aging, uniform structure, coefficient minimum, the internal stress completely disappear, not deformed, so the precision is high.

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Precision Granite Base Can Improve Machine Tool Performances

Requirements are constantly increasing in mechanical engineering in general and in machine tool construction in particular. Achieving maximum precision and performance values without increasing costs are constant challenges to being competitive. The machine tool bed is a decisive factor here. Therefore, more and more machine tool manufacturers are relying on granite. Due to its physical parameters, it offers clear advantages that cannot be achieved with steel or polymer concrete.

Granite is a so-called volcanic deep rock and has a very dense and homogeneous structure with an extremely low coefficient of expansion, low thermal conductivity and high vibration damping.

Below you will discover why the common opinion that granite is mainly only suitable as machine base for high-end coordinate measuring machines is long outdated and why this natural material as a machine tool base is a very advantageous alternative to steel or cast iron even for high-precision machine tools.

We can manufacture granite components for dynamic motion, granite components for linear motors, granite components for ndt, granite components for xray, granite components for cmm, granite components for cnc, granite precision for laser, granite components for aerospace, granite components for precision stages...

High Added Value Without Additional Costs
The increasing use of granite in mechanical engineering is not so much due to the massive increase in the price of steel. Rather, it is because the added value for the machine tool achieved with a machine bed made of granite is possible at very little or no extra cost. This is proven by cost comparisons of well-known machine tool manufacturers in Germany and Europe.

The considerable gain in thermodynamic stability, vibration damping and long-term precision made possible by granite cannot be achieved with a cast iron or steel bed, or only at relatively high cost. For example, thermal errors can account for up to 75% of the total error of a machine, with compensation often attempted for by software – with moderate success. Due to its low thermal conductivity, granite is the better foundation for long-term precision.

With a tolerance of 1 μm, granite easily meets the flatness requirements according to DIN 876 for the degree of accuracy 00. With a value of 6 on the hardness scale 1 to 10, it is extremely hard, and with its specific weight of 2.8g/cm³ it almost reaches the value of aluminium. This also results in additional advantages such as higher feed rates, higher axis accelerations and an extension of the tool life for cutting machine tools. Thus, the change from a cast bed to a granite machine bed moves the machine tool in question into the high-end class in terms of precision and performance – at no extra cost.

Granite’s Improved Ecological Footprint
In contrast to materials such as steel or cast iron, natural stone does not have to be produced with a great deal of energy and using additives. Only relatively small amounts of energy are required for quarrying and surface treatment. This results in a superior ecological footprint, which even at the end of a machine’s life surpasses that of steel as a material. The granite bed can be the basis for a new machine or be used for completely different purposes such as shredding for road construction.

Nor are there any shortages of resources for granite. It is a deep rock formed from magma within the earth’s crust. It has ‘matured’ for millions of years and is available in very large quantities as a natural resource on almost all continents, including all of Europe.

Conclusion: The numerous demonstrable advantages of granite compared to steel or cast iron justify the increasing willingness of mechanical engineers to use this natural material as a foundation for high-precision, high-performance machine tools. Detailed information about granite properties, which are advantageous for machine tools and mechanical engineering, can be found in this further article.

A repeat measurement is a measurement of local flatness areas. The Repeat Measurement specification states that a measurement taken anywhere on the surface of a plate will repeat within the stated tolerance. Controlling local area flatness tighter than overall flatness guarantees a gradual change in surface flatness profile thereby minimizing local errors.

Most manufacturers, including imported brands, adhere to the Federal Specification of overall flatness tolerances but many overlook the repeat measurements. Many of the low value or budget plates available in the market today will not guarantee repeat measurements. A manufacturer who does not guarantee repeat measurements is NOT producing plates that meet the requirements of ASME B89.3.7-2013 or Federal Specification GGG-P-463c, or DIN 876, GB, JJS...

Both are critical to ensure a precision surface for accurate measurements. Flatness specification alone is not sufficient to guarantee measurement accuracy. Take as an example, a 36 X 48 Inspection Grade A surface plate, which meets ONLY the flatness specification of .000300". If the piece being checked bridges several peaks, and the gage being used is in a low spot, the measurement error could be the full tolerance in one area, 000300"! Actually, it can be much higher if the gage is resting on the slope of an incline.

Errors of .000600"-.000800" are possible, depending upon the severity of the slope, and the arm length of the gage being used. If this plate had a Repeat Measurement specification of .000050"F.I.R. then the measurement error would be less than .000050" regardless of where the measurement is taken on the plate. Another problem, which usually arises when an untrained technician attempts to resurface a plate on-site, is the use of Repeat Measurements alone to certify a plate.

The instruments that are used to verify repeatability are NOT designed to check overall flatness. When set to zero on a perfectly curved surface, they will continue to read zero, whether that surface is perfectly flat or perfectly concave or convex 1/2"! They simply verify the uniformity of the surface, not the flatness. Only a plate that meets both the flatness specification AND the repeat measurement specification truly meets the requirements of ASME B89.3.7-2013  or Federal Specification GGG-P-463c.

Ask us about or flatness specification and repeat measurement promise by calling +86 19969991659 or emailing INFO@ZHHIMG.COM

Yes, but they can only be guaranteed for a specific vertical temperature gradient. The effects of thermal expansion on the plate could easily cause a change in accuracy greater than the tolerance if there is a change in the gradient. In some cases, if the tolerance is tight enough, the heat absorbed from overhead lighting can cause enough of a gradient change over several hours.

Granite has a coefficient of thermal expansion of approximately .0000035 inches per inch per 1°F. As an example: A 36" x 48" x 8" surface plate has an accuracy of .000075" (1/2 of Grade AA) at a gradient of 0°F, the top and bottom are the same temperature. If the top of the plate warms up to the point where it is 1°F warmer than the bottom, the accuracy would change to .000275" convex ! Therefore, ordering a plate with a tolerance tighter than Laboratory Grade AA should only be considered if there is adequate climate control.

A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface.

The plate should be supported at these points during production, and it should be supported only at these three points while in use. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same 3 points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. All zhhimg steel stands have support beams designed to line up with the proper support points.

If the plate is properly supported, precise leveling is only necessary if your application calls for it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Why Choose Granite for Machine Bases and Metrology Components?

The answer is 'yes' for almost every application. The advantages of granite include: No rust or corrosion, almost immune to warping, no compensating hump when nicked, longer wear life, smoother action, greater precision, virtually non-magnetic, low co-efficient of thermal expansion, and low maintenance cost.

Granite is a type of igneous rock quarried for its extreme strength, density, durability, and resistance to corrosion. But granite is also very versatile– it’s not just for squares and rectangles! In fact, Starrett Tru-Stone confidently works with granite components engineered in shapes, angles, and curves of all variations on a regular basis—with excellent outcomes.

Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:

machineable
precisely flat when cut and finished
rust resistant
durable
long lasting
Granite components are also easy to clean. When creating custom designs, be sure to choose granite for its superior benefits.

STANDARDS / HIGH WEAR APPLICATIONS
The granite utilized by ZhongHui for our standard surface plate products has high quartz content, which provides greater resistance to wear and damage. Our Superior Black and Crystal Pink colors have low water absorption rates, minimizing the possibility of your precision gages rusting while setting on the plates. The colors of granite offered by ZhongHui result in less glare, which means less eyestrain for individuals using the plates. We have chosen our granite types while considering thermal expansion in an effort to keep this aspect minimal.

CUSTOM APPLICATIONS
When your application calls for a plate with custom shapes, threaded inserts, slots or other machining, you’ll want to select a material like Black Diabase. This natural material offers superior stiffness, excellent vibration dampening, and improved machinability.

Yes, if they are not too badly worn. Our factory setting and equipment allow the optimum conditions for proper plate calibration and rework if necessary. Generally, if a plate is within .001" of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than .001" out of tolerance, or if it is badly pitted or nicked, then it will need to be sent to the factory for grinding prior to relapping.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. We urge you to use caution in selecting your calibration service. Ask for accreditation and verify the equipment that the technician will use has a National Inspection Institution traceable calibration. It takes many years to learn how to properly lap precision granite.

ZhongHui provides quick turn-around on calibrations performed in our factory. Send your plates in for calibration if possible. Your quality and reputation depend on the accuracy of your measurement instruments including surface plates!

Our black surface plates have a significantly higher density and are up to three times as stiff. Therefore, a plate made of the black does not need to be as thick as a granite plate of the same size to have equal or greater resistance to deflection. Reduced thickness means less weight and lower shipping costs.

Beware of others who use lower quality black granite in the same thickness. As stated above, properties of granite, like wood or metal, vary by material and color, and is not an accurate predictor of stiffness, hardness, or wear resistance. In fact, many types of black granite and diabase are very soft and not suitable for surface plate applications.

No. The specialized equipment and training necessary to rework these items requires that they be returned to the factory for calibration and rework.

Yes. Ceramic and granite have similar characteristics, and the methods used to calibrate and lap granite can be used with ceramic items as well. Ceramics are more difficult to lap than granite resulting in a higher cost.

Yes, provided that the inserts are recessed below the surface. If steel inserts are flush with, or above the surface plane, they must be spot-faced down before the plate can be lapped. If required, we can provide that service.

Yes. Steel inserts with the desired thread (English or metric) can be epoxy bonded into the plate at the desired locations. ZhongHui uses CNC machines to provide the tightest insert locations within +/- 0.005”. For less critical inserts, our locational tolerance for threaded inserts is ±.060". Other options include steel T-Bars and dovetail slots machined directly into the granite.

Inserts that are properly bonded using high strength epoxy and good workmanship will withstand a great deal of torsional and shear force. In a recent test, using 3/8"-16 threaded inserts, an independent testing laboratory measured the force required to pull an epoxy-bonded insert from a surface plate. Ten plates were tested. Out of these ten, in nine cases, the granite fractured first. The average load at the point of failure was 10,020 lbs. for gray granite and 12,310 lbs. for black. In the single case where an insert pulled free of the plate, the load at the point of failure was 12,990 lbs.! If a work piece forms a bridge across the insert and extreme torque is applied, it is possible to generate enough force to fracture the granite. Partially for this reason, ZhongHui gives guidelines for the maximum safe torque that can be applied the epoxy bonded inserts: https://www.zhhimg.com/standard-thread-inserts-product/

Yes, but only at our factory. At our plant, we can restore almost any plate to 'like-new' condition, usually for less than half the cost of replacing it. Damaged edges can be cosmetically patched, deep grooves, nicks, and pits can be ground out, and the attached supports can be replaced. In addition, we can modify your plate to increase its versatility by adding solid or threaded steel inserts and cutting slots or clamping lips, per your specifications.

Why Choose Granite?
Granite is a type of igneous rock formed in the Earth millions of years ago. The composition of igneous rock contained many minerals such as quartz that is extremely hard and wear-resistant. In addition to hardness and wear resistance granite has approximately half the coefficient of expansion as cast iron. As its volumetric weight is approximately one third that of cast iron, granite is easier to manoeuvre.

For machine bases and metrology components, black granite is the colour most used. Black granite has a higher percentage of quartz than other colours and is, therefore, the hardest wearing.

Granite is cost-effective, and cut surfaces can be exceptionally flat. Not only can it be hand lapped to achieve extremes of accuracy, but re-conditioning can be performed without moving the plate or table off-site. It is entirely a hand lapping operation and generally costs much less than re-conditioning a cast iron alternative.

These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components such as the granite surface plate.

ZhongHui produces bespoke granite products that are created to support specific measurement requirements. These bespoke items vary from straight edges to tri squares. Due to the versatile nature of granite, the components can be produced to any size required; they are hard wearing and long-lasting.

Advantages of Granite Surface Plates
The importance of measuring on an even surface was established by British inventor Henry Maudsley in the 1800s. As a machine tool innovator, he determined that consistent production of parts required a solid surface for reliable measurements.

The industrial revolution created a demand for measuring surfaces, so engineering company Crown Windley created manufacturing standards. The standards for surface plates were first set by Crown in 1904 using metal. As the demand and cost for metal increased, alternative materials for the measuring surface were investigated.

In America, monument creator Wallace Herman established that black granite was an excellent surface plate material alternative to metal. As granite is non-magnetic and doesn’t rust, it soon became the preferred measuring surface.

A granite surface plate is an essential investment for laboratories and test facilities. A granite surface plate of 600 x 600 mm can be mounted on a support stand. The stands provide a working height of 34” (0.86m) with five adjustable points for levelling.

For reliable and consistent measurement results, a granite surface plate is crucial. As the surface is a smooth and stable plane, it enables instruments to be carefully manipulated.

The main advantages of granite surface plates are:

• Non-reflective
• Resistant to chemicals and corrosion
• Low coefficient of expansion compared with cart iron so less affected by temperature change
• Naturally rigid and hard-wearing
• The plane of the surface is unaffected if scratched
• Will not rust
• Non-magnetic
• Easy to clean and maintain
• Calibration and resurfacing can be done onsite
• Suitable for drilling for threaded support inserts
• High vibration damping

For many shops, inspection rooms and laboratories, precision granite surface plates are relied on as the basis for accurate measurement. Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining. They also are ideal bases for making height measurements and gaging surfaces. Further, a high degree of flatness, stability, overall quality and workmanship make them a good choice for mounting sophisticated mechanical, electronic and optical gaging systems. For any of these measurement processes, it is imperative to keep surface plates calibrated.

Repeat Measurements and Flatness
Both flatness and repeat measurements are critical to ensure a precision surface. Flatness can be considered as all points on the surface being contained within two parallel planes, the base plane and the roof plane. The measurement of distance between the planes is the overall flatness of the surface. This flatness measurement commonly carries a tolerance and may include a grade designation.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:
Laboratory Grade AA = (40 + diagonal² / 25) x 0.000001 inch (unilateral)
Inspection Grade A = Laboratory Grade AA x 2
Tool Room Grade B = Laboratory Grade AA x 4

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

To ensure a surface plate meets both the flatness and repeat measurement specifications, manufacturers of granite surface plates should use Federal Specification GGG-P-463c as a basis for their specifications. This standard addresses repeat measurement accuracy, material properties of surface plate granites, surface finish, support point location, stiffness, acceptable methods of inspection and installation of threaded inserts.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

Checking Plate Accuracy
By following a few simple guidelines, an investment in a granite surface plate should last for many years. Depending on plate usage, shop environment and required accuracy, frequency of checking the surface plate accuracy varies. A general rule of thumb is for a new plate to receive a full recalibration within one year of purchase. If the plate is used frequently, it is advisable to shorten this interval to six months.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations
In some cases, there are variations between surface plate calibrations. Sometimes factors such as surface change resulting from wear, incorrect use of inspection equipment or use of noncalibrated equipment can account for these variations. The two most common factors, however, are temperature and support.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

It is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages. Cover plates to protect them from dust and damage. Wear life can be extended by covering the plate when not in use.

Extend Plate Life
Following a few guidelines will reduce wear on a granite surface plate and ultimately, extend its life.

First, it is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Rotate the plate periodically so that a single area does not receive excessive use. Also, it is recommended to replace steel contact pads on gaging with carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap
When a granite surface plate needs re-surfacing, consider whether to have this service performed on-site or at the calibration facility. It is always preferable to have the plate relapped at the factory or a dedicated facility. If, however, the plate is not too badly worn, generally within 0.001 inch of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than 0.001 inch out of tolerance, or if it is badly pitted or nicked, then it should be sent to the factory for grinding prior to relapping.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. Ask for accreditation and verify the equipment that the technician will use has a NIST-traceable calibration. Experience also is an important factor, as it takes many years to learn how to correctly lap precision granite.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.

Checklist for Calibration Variations

1. The surface was washed with a hot or cold solution prior to calibration and was not allowed sufficient time to normalize.
2. The plate is improperly supported.
3. Temperature change.
4. Drafts.
5. Direct sunlight or other radiant heat on the surface of the plate. Be sure that overhead lighting is not heating the surface.
6. Variations in the vertical temperature gradient between winter and summer. If at all possible, know the vertical gradient temperature at the time the calibration is performed.
7. Plate not allowed sufficient time to normalize after shipment.
8. Improper use of inspection equipment or use of noncalibrated equipment.
9. Surface change resulting from wear.

Tech Tips
Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining.

Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.