Acetal is a thermoplastic that is white by nature. Being a thermoplastic, it can be melted down and reformed making it a useful plastic for recycling. Acetal goes by several names including POM and polyacetal and brand names like Delrin which is manufactured by DuPont.
Acetal is an extremely strong plastic that is hard, ridged, and perfect for applications requiring great strength to weight ratio. Acetal is found in a wide range of common applications including eyeglass frames, ball bearings, and locks.
Acetal can be formed using a number of common manufacturing techniques including CNCs, manual tools, and laser cutting. Interestingly, the thermoplastic properties of acetal also allow for it to be used with plastic injection machinery.
Acetal is ideal for laser cutting thanks to its ability to absorb CO2 laser beams, though it is important to ensure adequate extraction when cutting this material. Laser cutters are also ideal for acetal thanks to their great precision, accuracy, and repeatability meaning that laser-cut acetal can be used for any project whether it’s a prototype or a full production run. Furthermore, the ability for laser cutters to easily create identical copies of a design allows for prototypes to instantly move to mass production with no design changes.
Generally speaking, any material that can be cut with a laser can also be engraved with a laser. In the case of acetal, laser engraving is perfect for a multitude of reasons. The first is that engraving acetal with a laser requires a small layer of acetal to be physically removed. This removal creates an engraving that is impossible to remove without aggressively sanding the entire surface.
The second reason why engraving is ideal for laser-cut acetal is that the engraving process occurs at the same times as the laser cutting. This not only increases the manufacturing speed of parts, but also creates engravings that are precisely positioned relative to the part being engraved.
Thirdly, engraving acetal can potentially remove the need for further marking or printing onto the acetal surface. Details such as instructions and warnings can easily be engraved to the surface of acetal, and the longevity of engraved features ensures that important designs and information lasts for the entire lifecycle of the part.
Acetal has an extremely wide range of applications thanks to its high strength, low weight, and smooth surface finish. For example, acetal is frequently used in small mechanical parts such as gears and cogs, and this is possible thanks to the smooth qualities of acetal.
Acetal can also be used with enclosures as the high strength capabilities of acetal can provide adequate protection for sensitive electronics and other components. The high strength of acetal also makes it ideal for use in furniture and packaging. Acetal is also very commonly found in consumer products including musical instruments, models, and keyboards due to its versatility.
Ponoko stocks a range of different thicknesses of acetal and three main colors: green, white, and black. The largest thickness of acetal available is 4.9mm while the thinnest sheets are 0.8mm. For more color variations, other plastics such as acrylic can be considered.
The smoothness of acetal makes it fantastic for low-friction applications, but this smoothness comes at a cost. Simply put, acetal is one of the harder plastics to glue and creates unreliable bonds with glue due to the extreme smoothness of the surface and the inability to form strong bonds.
Adhesion can be improved by roughing the surface of acetal (most materials can take advantage of this technique), but even then, most glues have a hard time adhering to acetal. If acetal parts are to be connected to other parts the engineers should consider using mechanical fixtures such as nuts and bolts.
The thermoplastic properties of acetal allow for it to be melted and reformed, and this means that acetal is an ideal plastic for recycling. Old acetal can be ground down into a powder, formed into pellets, and then these pellets can be fed into a plastic injection molding machine to make new parts or sheets.