FAQs About Thermoforming
Here are a list of frequently asked questions about thermoforming that Techniform Industries has encountered through the years. See something not answered, please feel free to drop us a quick note with the form to the right!
What is thermoforming?
Thermoforming is a generic term for the process of producing plastic parts from a flat sheet of plastic under temperature and pressure. In the highest expression of the technology, thermoforming offers close tolerances, tight specifications, and sharp detail. When combined with advanced finishing techniques, high-technology thermoforming results in products comparable to those formed by injection molding. All of us are exposed to many thermoformed plastics in our daily lives. They have replaced many parts previously manufactured from wood, paper, glass, and metal.
What are the benefits of thermoforming?
Thermoforming is efficient and very cost-effective for the production of many plastic parts depending on their size, shape, and quantity. Initial project costs are usually much lower, and lead times to tooling and production are generally much shorter than other processes. Modifications to design often times may be achieved. Temporary tooling offers an inexpensive short-term test for design issues and product market acceptance.
When and where does thermoforming fit?
Almost everything is well-suited to the thermoforming process. Tooling costs are considerably less than injection molding, which may have cost-prohibitive tooling costs. Parts with features mostly confined to one side of the part are best suited to thermoforming, but features on the uncontrolled side of the part may be addressed by trimming or fabrication and assembly.
What are average lead times when thermoforming?
Our sales and engineering team will work closely with you to understand your time constraints and do everything possible to meet or exceed your expectations.
Are there minimum quantities when it comes to thermoforming, twin sheet forming, vacuum forming, or pressure forming?
We don’t have a set minimum. It really depends upon the requirements of the packaging design and materials used. However, keep in mind that the larger the order, the more we can save you in per-part costs.
Do you ship thermoformed products worldwide?
Yes, we have the capability to ship worldwide. However; some countries have some packaging materials restrictions so it’s best to send us your specific shipping question(s) and packaging needs with our Quick Request Form and we will get back to you with the specifics you need.
In thermoforming, I understand you can only control one side of the part during the plastic forming process. Why is this?
The side of the plastic formed against the mold can be controlled with close tolerances. The side away from the mold cannot be controlled although it can be predicted what will occur on the uncontrolled side. Tolerance requirements on the uncontrolled side are addressed by trimming or fabrication and assembly.
How thick of materials do we work with when thermoforming?
We typically deal with materials ranging in thickness from .040" to .500".
What type of plastics can you thermoform?
Plastics that lend themselves best to thermoforming are: acrylonitrile-butadiene-styrene copolymer (ABS), high-impact polystyrene (HIPS), high density polyethylene (HDPE), high molecular weight polyethylene (HMWPE), polypropylene (PP), polyvinyl chloride (PVC), polymethyl methacrylate (or "acrylic") (PMMA), and polyethylene terephthalate modified with CHDM (PETG).
What kind of cosmetic features can be achieved with thermoforming?
Sharp, crisp detail with close tolerances can be achieved. Undercuts, formed-in texture, formed-in logos, formed-in hardware, and custom colors are just a few of the many features that can be accomplished with thermoforming.
What is twin-sheet forming and what type of parts
does the process of twin sheet forming allow to be thermoformed?
Twin-sheet forming is when two separate sheets are simultaneously formed in their respective separate molds to create hollow and double-walled parts comparable to roto-molded parts but with great detail and better appearances.
What other tooling is required in the thermoforming process?
A vacuum fixture is required when a part must be CNC trimmed. Vacuum fixtures are constructed by taking a reverse impression of the part and mounting this impression into a vacuum box. The trim fixture then holds, under vacuum pressure, each part being CNC trimmed to ensure consistent results. Other tooling specifically required in the forming, trimming, fabrication, and assembly of each part is designed by engineers and constructed by the tooling department.
What kinds of thermoforming molds are there?
Machined Aluminum Molds
Machined aluminum molds are typically created for shallow parts with small draw ratios. We use aluminum for the construction of molds, which can be held to very close tolerances. These molds are mounted on a temperature control base to control the mold temperature during the forming process. Female or male molds whether vacuum formed or pressure formed thermoformed molds can be machined aluminum molds. These same molds can then be textured and may then offer distinct features such as loose cores, pneumatic cores, and even inserts.
Cast Aluminum Molds
Cast aluminum molds are cast at a foundry from a pattern machined from a composite material. The temperature controls are then cast into the sides and back of the cast aluminum molds at the foundry. They are typically built for parts with large draw ratios and may be female or male and vacuum formed or pressure formed. Features such as texture, loose and pneumatic cores, and inserts are also available by Techniform.
For prototyping and short production runs, cost-efficient composite materials are used for mold construction. These molds produce parts that are to be evaluated for fit, form, and function and may be modified to evaluate possible design changes. These molds are for vacuum-forming only and are not temperature controlled. These molds have a limited life.
Custom Plastic Thermoforming Glossary of Terms
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