Frequently Asked Questions
At ETI, we have worked with a wide variety of industrial and commercial clients on unique molding and die cutting projects for over 30 years. During that time, we have encountered several common questions about the types of services and capabilities we offer-we aim to help clarify them here.
1. What do I need to consider to design a part for molding/die cutting?
- The parts' mechanical use and appearance.
Mechanical and environmental requirements will dictate the type of material to be used and in turn may determine the process used to make the part. Geometry influences the cost and manufacturing feasibility of tooling and parts.
- The environment in which it will operate.
To produce parts that will stand the test of time, you must consider the environmental conditions and mechanical demands that will be involved in the end application. One must consider many factors such as exposure to sunlight, ambient light, temperature, fresh or salt water, oils, solvents, chemicals, abrasion, compression, elasticity, lateral stresses, and hardness.
- The choice of material usually depends on the above aspects as well.
The two biggest decisions in any part molding project are selecting the final design and choosing the appropriate material to achieve the desired functionality of the component. Material selection is crucial. Choosing a material that does not match up well to the conditions of the end application can end in failure of parts or assemblies. Quality, function, repeatability, and reliability are dependent upon material choice. Your molded part manufacturer should be able to work closely with you and recommend the best fitting material for your needs.
- The most ideal process for your part will follow based on material selection.
Before choosing a molding process for your next part production project, it is important to understand the differences between all the process types, as each offers its own advantages and best use cases.
Here are some resources for the process types we offer at ETI:
- Liquid Injection Molding
- Die Cutting
- Compression Molding
- Injection Molding Prototyping
- Rubber Molding
- Transfer Molding Service
2. Is my design ready to be built?
If we have the information about your intended application's conditions and specifications listed above, as well as a 3D part design and drawing, it is easier to decide. There are some aspects of a part design that can drive cost up or down. Some examples follow. Overly complex design may require additional tool construction time to achieve the design requirement of the part. Multiple colors/multiple materials, the immediate availability of chosen materials, minimum order requirements of some material and other factors must be considered in the part design to ensure the part is capable of being made in a timely and cost-effective manner.
3. I need a small number of prototype parts. Is this possible?
The goal of prototyping usually leads you to an appropriate process-if prototyping would indeed make sense for your budget.
There are several advantages to prototyping, which include the ability to experiment with and learn from the prototypes to see if they are able to perform the required function or that they fit into an assembly properly. However, one common misconception and sometimes unnecessary spend point during liquid injection molding (LIM) projects is prototype production. Typically, a LIM prototyping process results in hundreds and even thousands of qualification parts that need to be evaluated. The tooling as well as the materials and qualification runs of the product can be quite expensive. Customers should have a clear objective in mind before they request prototypes from a service provider. Another less costly, more time efficient option might be available.
4. Can you make me some small/large amounts of production parts?
A key point to consider at the beginning of a project is that the material, tooling, and selected molding process will dictate throughput. Compared to alternative molding methods, injection molding is more economical, especially for high volumes of medium to high complexity products. For lower quantities, compression molding and transfer molding offer lower up-front cost advantages.
5. What will a mold cost?
The cost of a mold is related to the specification and design for the part and the process that is selected to get you there. The manufacturer of your parts should be able to give you a clear idea of costs involved depending on requested part features and all other aspects of your project. Our Project Forecaster can help us determine a suggested material and process for producing your part.
6. Does ETI build its own tooling?
No-we choose to not carry this cost overhead. We work with a variety of local tool shops to ensure we are equipped with the appropriate tooling for each project.
7. What will my parts cost?
Part cost is related to a part's design, the material selected, the type and number of cavities in the mold purchased, the process used to make it, and the quality control needed to repeat it. Some materials are easier to process, which lessens the cost to make a part, while other materials require secondary operations that add to the cost of a part. All of these factors-along with the time it takes to mold and process after molding-relates to the part cost.
We are best able to advise our customers on cost if they first complete our brief Design Analysis form or call us to discuss.
8. What kinds of materials should I use for my parts?
You need to evaluate the material in terms of its performance data, appearance, cost, and the environment the parts will be used in. For example: silicone is a popular and versatile material that features excellent performance within a broad temperature range. Cost, delivery, lead time, material availability, and part and assembly design features all apply to material selection. It's also important to consider that flash will almost inevitably occur on the parting lines of tooling used with silicone-based material. If you are looking for a flash-free end product, silicone might not be the best match.
9. Can I get colored parts?
Yes, usually. Some materials color better than other materials; silicone is more of a challenge to paint and print, for instance. The process selected will also influence color options-compression molding and transfer molding in particular offer colored material options but the appearance must be weighed carefully against your expectations. Some materials cannot be colored without negative impact to the materials properties or due to their chemical composition.
10. Can I get parts without any flash on them?
Rubber molds flash to some extent. Some more than others (particularly silicone in liquid injection molding). It is a matter of what to do with the flash if it occurs. Flash will become more pronounced over time as molds wear. There are a variety of processes for removing flash-known as de-flashing-such as trimming or the use of liquid nitrogen in a machine that allows the flash to be removed mechanically. The type of de-flashing-hand-operated or by machine, for example-that is employed is typically based on the volume of molded parts, the part's design, and where the flash occurs.
11. What dimensional tolerances can you hold on molded parts/die cut parts?
It depends on the parts' design, selected material, and tooling. We will be able to give a clearer understanding for your specific parts with information provided to us in the Design Analysis Project Forecaster or in a discussion about design intent. It's important to consider that a closer tolerance and a more complex part design may require secondary operations and more expensive tooling choices. Also, dimensional or thickness requirements for die cut parts might be problematic for part quality and require a different approach to making usable parts.
12. Are there alternative processes to getting the parts I want?
There might well be. We might recommend a different path to production if we believe it is in everyone's best interest. For example, if a customer reaches out to us requesting liquid injection edits 20010molding to be performed with a silicone material, but their end application operating conditions involve more extreme chemical and environmental conditions (i.e. pressurized steam at temperatures over 150°C, which tend to cause a breakdown of silicone's siloxane polymer and a decline in its properties), we might recommend a material change which could lead to an alternative process. We are always happy to talk about possibilities and have experts outside ETI that are willing to help as well.