Self-Tapping Screws For Plastic.

What are Self-Tapping Screws For Plastic?

Self-tapping screws for plastic are specialised fasteners engineered to cut their own threads into plastic components, including injection moulded parts and 3D printed assemblies. Unlike general-purpose self-tapping screws, these thread forming screws for plastic are optimised for medium and low-density plastic materials, ensuring a strong mechanical bond without the need for pre-threaded holes or inserts.

For example, when assembling a 3D printed enclosure, using a standard screw can risk bulging and splitting pre-drilled holes or even forcing print layers apart. Even without visible damage, this fixing method can present unreliability and low resistance to pullout.

A specially designed self-tapping plastic screw, such as Accu’s PlasTech 30 or PolyFix 30 screws, prevents this by precisely cutting into the material with reduced radial stress delivering secure fastening without compromising part integrity.

How Self-Threading Screws for Plastic Work

These self-threading plastic screws work by forming threads directly into pre-drilled or 3d-printed plastic holes. Our engineering team believe these are the best screws for plastic thanks to their two key design elements: the specialised thread profile and the trilobular shaft.

Thread Profile

PolyFix and PlasTech screws feature extremely sharp thread geometries designed to cut cleanly into plastics, especially when compared to other fasteners such as wood screws.

PolyFix/PlasTech 30 screws use a 30° thread angle, making them ideal for soft plastics. This sharper angle exerts significantly less radial force, reducing the risk of material deformation.

PolyFix/PlasTech 45 screws, on the other hand, use a 45° thread angle, balancing cutting efficiency and grip strength for medium-density plastics.

Trilobular Shaft

The trilobular shaft, a three-lobed geometry, minimises radial force during installation. This trilobular design includes recessed relief areas that allow displaced plastic to settle into them, significantly reducing the risk of bulging or cracking. This makes these screws especially effective in thin-walled parts or 3d-printed plastic housings.

Materials Self-Tapping Screws for Plastic Are Made From

Accu supplies metal screws for plastic in the following material options:

• Stainless Steel (A2): Our stainless steel screws for plastic offer superior corrosion resistance and long-term durability, ideal for harsh environments or applications where the fastener is visible and must retain its appearance.
• Carbon Steel: Delivers high strength and cost-efficiency, well-suited for general applications where extreme corrosion resistance is not a primary concern.

To meet different environmental and aesthetic requirements, several finish options are available on our carbon steel and stainless steel self tapping screws for plastic:

• Black Oxide Coating: Available for both stainless and carbon steel. This finish provides a low-glare, matte appearance and a moderate degree of corrosion resistance.
• Bright Zinc Plating: Exclusive to carbon steel. It offers a clean, reflective finish with enhanced protection against oxidation.

Sizes and Types of Self-Tapping Screws for Plastic Available

To support a broad range of prototyping applications to assembly scenarios, Accu’s selection of small screws for plastic includes:

• Thread Profiles: 30° is ideal for soft plastics and delicate housings. 45° is more suited for medium-density plastics.
• Head Types: Countersunk, Pan and Flanged Button for a range of flush and even load distribution needs.
• Drive Types: Pozi, Torx and Phillips. Often aligned with available tooling or resistance needs against cam-out.
• Thread Sizes: From 1.8mm to 5mm major diameter.
• Lengths: Ranging from 5mm to 40mm

These vast array of coarse thread screws for plastic provide flexibility for everything from micro-assemblies to large-scale plastic enclosures.

FAQs

Q: Can you screw directly into plastic?

A: Not without first drilling a pilot hole. You also need to use our specifically self-tapping screws for plastic which are designed to create their own strong threads into pilot holes without the need for the separate process of tapping threads. They also reduce splitting and bulging, often associated with hardware store fasteners.

Q: What screws to use to repair plastic?

For the best results use thread forming or self-tapping screws like PolyFix screws, which are engineered to cut cleanly into plastic without causing cracking, splitting, bulging or stress.

Q: What screws are used to join plastic?

Thread forming screws with trilobular shafts are most effective, as they provide strong, vibration-resistant joints without damaging the plastic. Just make sure to drill pilot holes prior to installation to help align panels and for clean self-tapping threads.

Q: Will self-tapping screws hold in plastic?

Regular, off the shelf self tapping fasteners are not the best choice when looking for self tapping screws for plastic. This is because they can often split or crack the workpiece they are installed. Instead opt for specially engineered thread forming screws for plastic that specifically reduce bulging and splitting of the material.

Q: What screw is best for plastic?

The best type of screw for plastics are our PolyFix/PlasTech 30 and 45 screws.  Referring to their thread profiles, the 30° profile are best for soft plastics, while the 45° profile screws suit medium density plastics. Choosing the right thread angle helps avoid deformation and ensures durability.

Q: What are the best screws for 3d printed parts?

A: Polyfix screws are amazing for 3D printed parts, offering secure grip with reduced stress on layer lines thanks to their thread-cutting profile and trilobular design.

Q: Can you screw into 3d printed plastic?

A: Yes. Accu's range of self-tapping and thread cutting screws for plastic are ideal for screwing into 3D printed plastic, minimising risk of layer splitting and allowing for multiple assembly and disassembly cycles.

Bespoke Self-Tapping Screws For Plastic Manufacture.

High precision, bespoke manufacture of Self-Tapping Screws For Plastic to customer specification. State of the art facilities specialising in both small batch prototyping and large scale manufacture.