Screws for Plastic Assemblies

The best solution for direct assembly into plastic

Screws for plastic are specifically designed for direct assembly into plastic materials with moulded pilot holes and they are the best alternative to standard fasteners or threaded inserts. Designed with a narrow flank angle (from 30º to 48º), they offer an increased pull-out resistance and reduce the risk of cracking the plastic.

Through their unique combination of lightweight, flexibility, durability and other intrinsic properties, plastic materials are used across a wide range of applications in different markets. Selecting the most appropriate screw to suit the plastic material would allow for thinner bosses which will reduce the overall assembly costs (reduce plastic material usage, installation time and the cost of injection parts).

Quick selector of thread forming screws for plastic

The table below offers a guide to select the screw to be use based on the type of plastic. Field tests will determine the optimal solution based on hole geometry, mechanical requirements and installation parameters.

The type of plastic is determined by its Bending Modulus (Flexural Modulus):

Ductile plastics < 1,900 MPa (< 275,571 psi): REMFORM^® screw
Medium plastics 1,900 - 2,999 MPa (275,571 - 434,968 psi): REMFORM^® screw
Hard plastics 3,000 - 6,850 MPa (435,113 - 993,508 psi): REMFORM^® II HS™ screw
Very Hard plastics > 6,850 MPa (> 993,508 psi): REMFORM^® II HS™ or REMFORM^® II F™ screw
Thermoset materials: REMFORM^® II F™ screw
Hard plastic and Low Thickness pieces: PCB screw
Soft plastic and Low Thickness pieces: TWINPLAST screw

Expert assistance and custom solutions

An optimal screw solution to be applied on plastic materials requires a detailed attention to the overall assembly process. Using standard self tapping screws is frequently causing assembly problems since plastic material is liable to burst due to stress during the assembly. We work in cooperation with our customers to find the best solution for the assembly on plastic materials, by analyzing plastic types, boss configurations, mechanical requirements and installation parameters.

Our technicians at CELO test laboratories provide technical reports with valuable data on screw capabilities for specific customer applications. Towards joint analysis and mechanical testing which include screw insertion, threading, failure, loosening torque and pull-out tests, we recommend the optimal solution to best meet your application requirements.

Additionally, to verify that the dimensions of the selected screws conform to your design, CELO offers you the possibility to download the 3D files of our products.