In investment casting, tooling refers to the creation of a metal “tool,” designed and built to customer-provided specifications or drawings. The tool is used to make wax patterns that, after additional process steps, will become the molds that form the final castings.
How to build a tooling?
The tool is made from high grade aluminum alloys or steel alloy, which designed to allow the flow of molten wax under extreme pressure, in order to allow it to solidify into the wax pattern which is used to form the ceramic mold during the investing process.
Unlike sand casting, investment casting tooling replicates the final casting in reverse, due to the fact that we cut “cavities” in which the wax flows to form our patterns. This tooling is often designed to be “collapsible”, in other words, it must be able to be taken apart to remove the solid wax patterns when they have cooled.
Another critical element of the tooling design is that the tooling must be constructed so that the wax patterns produced are larger than the final casting dimensions. This is due to the fact that metal shrinks during its solidification, so our engineers must calculate an expected shrinkage rate for every dimension in the tool, and apply those expected shrinkage rates when cutting the tooling. In the pattern tooling, any internal features can be produced, however if the various metal components of the tooling cannot be removed from the wax after solidification has taken place, a suitable method of coring will need to be utilized to form internal features.
Finally, the tooling can consist of simple single cavity varieties, or complex multi-cavity tools with automatic ejectors for higher volume jobs. CFS Investment Casting Foundry has a wide range of wax presses to accommodate most every tool design and size, as well as for all ranges of jobs from small volumes to large.
Tooling Cost is Charged
Due to the required tooling for developing a new investment cast part, at the time of the initial quotation, you will be quoted a piece price cost and a cooling cost. Most foundries will quote tooling as a separate item. This is usually a one time cost. It is wise to request that the investment caster describe the type of tooling they are quoting, whether manual, automatic, single or multi-cavity.
Tooling is usually considered to be the property of the customer after all outstanding invoices are paid. Tooling is normally stored and maintained in an operational condition by the investment casting foundry. It is critical that the issues of ownership and maintenance be clearly established at the beginning. The dimensions, material and structure will determine the tooling cost.
In most cases, tooling could be fixed if the original casting design is not ideal, but this will produce extra processing cost. When the clients revise their product structure, the tooling may need change accordingly.
If you want to know more about the tooling, you’s better know the process of lost-wax investment casting.
The tooling is a critical part of the investment casting process, the casting begins from the tooling. The importance of tooling in the investment casting process cannot be overstated, as it is essential for achieving the desired part geometry and for producing parts that meet the required specifications. The tooling must be of the highest quality in order to ensure that the castings are accurate and repeatable.
The dimensional accuracy of the casting, surface roughness and even some casting defects are all directly related to the quality of the tooling.
The materials of a tooling in the investment casting process
According to the different casting output, that is, the number of times the casting mold is used, the casting mold materials can be divided into steel, wood, cast iron, aluminum alloy, etc..
1, steel: in the past in the sand casting mold is mainly used to make standard parts and structural parts, less for the production of casting mold body, because the service life of carbon steel is not higher than ductile iron or low-alloy gray cast iron, and alloy steel is very expensive. However, with the improvement of mold processing technology and the casting mold dimensional stability requirements, mold steel, mold steel, chromium-molybdenum table gold steel is also used in the casting mold body.
Chrome-molybdenum alloy steel is also used to make casting molds. More and more steel is used to make mold base plate, core box frame and other I assembly parts. These casting molds used in the material now cast iron with more, because now the manual modeling will be gradually eliminated, with molding machine, core shooting machine, shell core machine modeling is the inevitable trend, with these modeling equipment modeling, casting mold on the back of more cast iron as raw materials.
2, wood mold: wood mold in China is still widely used, mostly for manual modeling or single piece of small batch production, production. However, with the improvement of environmental protection awareness and poor processing performance of wood restrictions, solid casting is gradually replacing wood casting.
3, solid casting: solid casting is a foam plastic sheet as the material, cut and paste into the required mold, after pouring and castings, the method is shorter than with wooden mold, short cycle time, low cost. The application of plastic mold is on the rise, especially the increasingly widespread application of machinable plastic.
4, aluminum alloy mold: aluminum alloy mold light weight, size accuracy and high, so its application is also more widely. But recently the application has a tendency to reduce, part of the market has been replaced by plastic mold and cast iron mold.
5, cast iron mold: cast iron mold is produced in large quantities of casting, it has the advantages of high strength, high hardness, good processability, low cost, long service life, etc., so it is loved by a large number of factories. In recent years, due to the improvement of casting level, there are more and more mold samples, mold base plate, type plate frame, etc. using higher strength and wear resistance of ductile iron or low diluted alloy gray cast iron production, and better heat-resistant fatigue performance of creeping graphite cast iron is also used for core box materials.
The casting mold material selection, according to the size of the mold, the complexity of the structure, the mold life requirements, as well as the cost of the mold to select materials.