Coupling

Terms of delivery:

1. Definition and scope

1.1Investmentcasting isa process by which a high surface quality can be manufacturedthrough theformation of dimensionally accurate casting.The patternsproduced by injection
moulding are heat disposable and are melted outafter manufacture of the ceramic moulds. The ceramic moulds aredestroyed after casting. For this reason, both the pattern and themoulds are designated lost using this method. Casting usually takesplace into hot moulds.

1.2 Metals and nickel-based alloys can be used for investment casting.

1.3Thistechnical memorandum does not apply precious metals cast using thedewaxing method,to productsof the jewellery industry,dentallaboratories or to art casting.

2. Purpose

2.1Thistechnical memorandum defines dimensional tolerances, specifies machiningallowances and surface roughness corresponding to the start of the art inthe field of investment casting. It serves as a basis for optimumeconomic cooperation between investment casting suppliers and buyers.

2.2Thespecifications mentioned hererefer to sand blasted preserved or pickledsurfaces in their delivered condition. Exception must be agreedwhere work processes are involved
which alter the dimensional tolerances.

2.3Unlessotherwise agreed,initial samples are supplied for first-timeorders.These are used to permit concrete mutual agreement betweensupplier and purchaser.Initial samples must be appraised by thebuyer,followed by a written release to the foundry for seriesproduction.Deviation acknowledged by the releaseor with positiveappraisal of theinitial samples are binding for the production processand must beentered intothe (casting) drawing.

3. Dimensional accuracy

3.1 Contraction and shrinkage
Duringthe solidification andcooling of cast metals, a contraction of thevolumenaturally occurs as aresult of shrinkage. Other factorsinfluencing the production of instrument
castingscan result fromtheshrinkage of the lost pattern and the expansion of moulds duringheating. The sum of these influencing factors is takenintoconsideration in the shrinkage
allowance during the manufacture ofinjection moulds. The shrinkage allowance is based on experiencevalues,depending on the contour of the casting, the ceramic shell andthe casting materials, as well as the casting techniques used in theindividual foundries.

3.2 Reference planes and reference points
Drawingused in the manufacture of casting must be gauged systematically usingreference orlocating points in order to ensure that dimensional checksand subsequentmachining are in agreement. Reference points must bedetermined right fromthe early design stage and coordinated betweenthezero position of thereference planes is precisely defined by means ofthe reference pointdimensions. All reference points must be arranged insuch a way that theyare not removed or altered during the subsequentmachining process.Reference points should be positioned on the outsidesurfaces of theinvestment casting.They may take the form of raised orreference pointsare beneficial when dealing with castings withrestricted shape andposition tolerances. When determining the referencepoints, attention should be paid to ensuring that they do not fall inthe area of asprue. In case of complex shaping,it is possible in thisway to position the casting precisely by(pre-)machining the locatingpoints.

3.3 Over definition
According to DIN 406, overde finition must be avoided. Wall thicknesses must always be specified.

3.4 Mould and draught angles
Mould and draught angles are not necessary as a general
rule.Exceptionsto this for reason of mould making or casting necessity must be agreedbetween the investment casting supplier and the buyer.

4. Dimensional tolerances

4.1 Linear dimensional tolerances
Achievable dimensional tolerances on investment casting are dependent on the following factors:
Casting material
Dimensions and shape of the casting
Validity of the accuracy grade

4.1.2. Dimensions and shape of the casting
Theachievable accuracy levelof the rated dimensions of an investmentcasting depends on the greatest dimension and the shape of thecasting.If the rated dimension(GTA)exceeds the rated dimension rangeindicated for acertain accuracy level,the overall tolerance of thecasting must be toleranced at the accuracy level (greatest tolerancefield). Deviation outside the accuracy level must be agreed between thesupplier and thebuyer.

Note: The technical info above are incomplete. Please contact us for more information.

Our Precision Investment Casting Technology has been applied in theproduction of:

A high standard of surface quality

Low material allowance on surfacesto be machined

Facility for complex shaped innercontours due to the use of ceramic cores

A high degree of dimensional accuracy due to elimination of the mould parting line usually responsible forcasting imprecision

Hardly any restrictions in terms of materials

Almost unlimited scope for the shaping of castings

The investment casting technique is characterized by

Summary

Generallyspeaking,the investment casting technique is used for small pieceweights of between 1g and 10 kg. Largerwork-pieces up to 150 kg are alsopossible.

Piece weights

Thecasting are produced without any trace of flash, and with an excellentsurface finish.In many cases-expect for producing the required seatdimensions there isno need for a follow-on machining process.

Surface quality

Allcastable materials can be processed using this method. Investmentcasting is particularly suitable for use with materials unsuited tomachining.

Material selection

Full service manufacturing of investment castings, including machining,heat treating, passivation, plating, polishing,and painting.

We offer stainless steel, carbon or alloy steel casting made by investment casting according to customer's design.

Material:316
Surface: Electro-polishing,machined