When considering acetal material for your design, it is important to understand the different properties each grade poses.
There are two basic grades of acetal available for machining; homopolymer acetal most commonly known as Delrin®, a registered trademark of Dupont™ (Dupont™ is the only manufacturer of homopolymer acetal resin) and copolymer acetal. Homopolymers are plastics with molecular chains containing identical DNA repeating of sequence, while copolymer contains two different DNA repeating units. The acetals look the same, and the chemistry is similar enough that both products are still considered acetals; however, they have large differences in properties, which if overlooked can cause failures and be costly.
Hompolymers and compolymers are not equal to one another, some large differences between the two are that copolymers have a lower water absorption rate and perform better than homopolymers in thermal, impact, wear, and chemical resistance. Homopolymers on the other hand have a higher crystallinity, and fatigue performance.
Homopolymers are also known to be susceptible to develop centerline porosity when they begin to cool during the manufacturing process because the exterior portions solidfy first, creating loss of volume in the interior. Centerline can typically be found as a small circle in the center of a part, as for sheets and rods, it will appear as a white stripe or band in the center or middle of the material.
The root cause of centerline porosity in acetal is due to gasses trying to escape the strict extruded “shell” that restrains volume change, causing voids or pockets to form. Centerline porosity can cause many undesirable effects in applications such as, weaken the part, provide a route for leakages of liquids and gasses, and permit bacterial growth in food processing and/or medical applications.
Copolymer is not as susceptible to develop centerline porosity, but it is indeed important to keep it in mind.
When requesting a quote and you want to make sure you are being quoted for the correct acetal, ask the sales representative to read the second level of the specification.
Tamshell Corporation machines all grades of acetal. To see if acetal will work for your design, call one our material experts today at 951-272-9395.
FAQ
We know every project is unique and that questions can arise when it comes to selecting the right partner for your manufacturing needs. Our team specializes in delivering precise, reliable machining solutions tailored to the exact specifications of each client. Below, we’ve gathered answers to some of the most commonly asked questions. If you don’t see your question here, please feel free to reach out – we’re always ready to assist with any additional information you need.
Tamshell specializes in producing a diverse array of custom precision machined components tailored to our customers’ specifications. Utilizing modern, advanced 4th & 5th axis CNC mills, CNC Swiss and Swiss-screw, and CNC turning machines, we achieve tight tolerances with nearly any machinable plastic or metal material.
Our primary machining department utilizes state-of-the-art CNC machining equipment to ensure precision and quality. The secondary department complements this with a variety of conventional tools and instruments. All our machinery is backed by our specialized in-house tooling department, ensuring seamless support and efficiency.
Our machine shop excels in precision machining of a wide range of materials, with a particular expertise in plastics. We also specialize in machining aluminum, brass, bronze, and stainless steel, ensuring high-quality results for diverse applications. Our advanced equipment and skilled team enable us to meet stringent tolerances and deliver custom components tailored to our clients’ specifications. Whether working with plastics or metals, we are committed to providing exceptional craftsmanship and reliable service.
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We excel in close tolerance machining, holding tolerances as tight as +/- 0.0001″. Our capabilities include advanced 4th- and 5th-axis machining, complemented by a rigorous three-stage inspection process. This ensures burr-free parts and consistently exceeds the highest-quality finish requirements.
In short: yes, our team brings extensive expertise in the manufacturability of components and assemblies. As specialists in plastics machining, our in-house material experts will guide you in selecting the most optimal materials for your application, considering all usage factors.
Our skilled machinists are also proficient in working with various materials, including metals. We can review your 3D models and drawings, recommending any necessary changes before production begins.