investment casting

OEM Investment Casting,Precisiom Casting, Lost Wax Casting,CNC Machining Parts

Investment Casting SS304 Stainless Steel Casting Parts

Senjia Heavy Industry focuses on the production and processing of casting parts, mainly producing carbon steel parts, stainless steel parts, alloy steel parts, etc.  We have a strong and highly efficient R&D team,which can design and make OEM/ODM products according to your ideas and samples.

What is investment casting

Investment casting process is made from wax model, such as its appearance is wrapped in a layer of clay refractory material, heat melt wax outflow, and the shell formed by refractory, again after the metal melt into the shell, after waiting for metal cooling will get the metal mould parts, refractory break the processing of metal is called precision casting technology, also known as investment casting or lost wax casting.  

Advantages and disadvantages of investment casting process  

Precision casting, also known as investment casting, investment casting has the following advantages compared with other casting methods and parts forming methods:  

1、 casting dimensional accuracy is high, surface roughness value is fine, casting dimensional accuracy can reach 4-6 level, surface roughness can reach 0.4 to 3.2μm, can greatly reduce the machining allowance of casting, and can achieve no margin manufacturing, reduce production cost.   

2、casting shape is complex, and difficult to process castings by other methods, casting outline size is small to a few millimeters to thousands of millimeters, the wall thickness is the thinnest 0.5mm, the smallest hole is below 1.0mm.  

3、alloy materials are not limited: such as carbon steel, stainless steel, alloy steel, copper alloy, aluminum alloy and high temperature alloy, titanium alloy and precious metals and other materials can be used for investment casting production, for difficult to forge, welding and cutting alloy materials, is especially suitable for investment casting production.  

4、high production flexibility, strong adaptability.  Can be used for mass production, also suitable for small batch or even single production.  

To sum up, precision casting has the advantages of small investment scale, large production capacity, low production cost, simple process for complex products and quick investment.  Thus, it is in a favorable position in the competition with other processes and production methods.  

However, wax mold production process, easy to appear the following defects  

1、 wax mold deformation, wax mold removed from the mold, in addition to the size of the reduction of change, sometimes due to the removal of incorrect manipulation caused by artificial deformation;  Because the wax mold in the cooling deflection deformation is common, so the wax mold just removed from the pressure is still carefully placed, usually with a larger plane as the datum flat, in addition, it may be too soft wax, pressure design is not reasonable and other factors.  

2、the wax mold filling dissatisfaction, the main reason is that the temperature of the wax is too low, injection speed is slow, the pressure temperature is low, resulting in the wax cooling fast in the process of flow, in the corner and the edge of the part or the wax mold thin wall part filling dissatisfaction, corners and corners of the place rounded, this situation is very similar to the casting of metal castings.  

3、 the surface of the wax mold wrinkles, because the wax temperature is too low, the rate of fire is too low, the wax movement and pressure temperature is not properly matched;  Or because the inner surface of the pressure type is damaged or not clean;  Cold metal blocks are improperly placed, leaving traces of movement on the wax surface.  Deep grooves, similar to cold insulation defects of metal castings;  There is in the core around, around the hole, sometimes visible joints, slightly sunken, is actually two strands of wax flow convergence failed to fuse, this is the wax temperature is not enough, pressure is not enough results.  

4、Wax mold surface sag is mainly caused by insufficient injection pressure and time, high wax temperature, insufficient cooling time, and sometimes too much mold release agent. The surface sag involves a large area, which is difficult to repair and easy to cause waste products.  

5、 wax mold there is a seam, which is the most common defect, that is, in the pressure type, pressure type combination block joint, core and core seat joint and other places have very thin wax sheet escape.  The main reason is that the pressure type precision is not enough, the pressure type parting surface or the joint surface of the internal parts of the type is damaged or contaminated, or the pressure is not enough and the injection pressure is too high.  Or the wax is too hot.  Hair wings must be completely removed before wax molds can be used.  

6、 wax mold and pressure stick, this is because there is no use of release agent, or the temperature of wax and pressure type are too high, or pressure type inner surface is not clean enough.  

7、 the surface of the wax mold is rough, because the injection pressure is too low, or the contact density of the wax material and the inner surface of the pressure is not enough, serious wrinkles will appear.   

8、 there are bubbles in the wax model, one is visible with the naked eye on the surface of the bubble, the other is the inner wax model of the bubble, usually larger, with the naked eye can not see, but can be found through the local wax model, which is caused by the expansion of the gas in the wax model.  

The dimensional accuracy of investment casting is high, generally up to CT4-6 (ct10~13 for sand casting and CT5 ~7 for die casting). Of course, due to the complex process ofinvestment casting, there are many factors affecting the dimensional accuracy of casting.   Such as shrinkage, deformation of investment casting mould materials, shell in the process of heating and cooling line quantity change, alloy of shrinkage and deformation of the casting during solidification, etc., so ordinary size although higher precision investment castings, but still need to improve the consistency (in medium and high temperature of the wax casting size consistency to improve a lot).   

Key points of investment casting technology  

1、Do not spray too much parting agent in the mold cavity.  

2、Pressing melting (wax) mold cycle parameters established, do not easily change.   

3、The wax mold should be placed in the storage plate and isolated from each other to avoid damage.  When necessary, fixture can be used to avoid wax mold deformation.  

4、Do not hurt the surface during the correction.  

Application scope of investment casting process  

Investment casting is almost used in all industrial sectors, especially electronics, petroleum, chemical, energy, transportation, light industry, textile, pharmaceutical, medical equipment, pumps and valves and other sectors.