top of page

How to correctly add metal inserts to plastic products?

Hello friends,The world of plastics is a vast field for application and at the same time requires us to delve into production methods. In the process of broadening the horizons that we go through, new and useful insights arise. Every new idea that provides an optimal answer to needs, brings with it great satisfaction and increases our desire to bring about more innovations. These include efficiency and a more perfect response for those who need it. This time we will talk about "inserts" and their importance.

Strong and durable screws are needed in many plastic products, especially when they are opened and closed many times. In such cases it is advisable to use metal "inserts". There are several methods for inserting "inserts" into plastic parts, each with advantages and disadvantages. In the article I will present the main methods:

insertion of "inserts" by an ultrasonic machine

In this case, the plastic part is produced with a drill that is adapted to the "insert" you want to use, important parameters are the diameter of the drill, depth and slope (in the case of conical drills). For the purpose of soldering, a bracket is made that is adapted to the part so that there is good support for the part and that the direction during insertion is vertical and accurate. Connect a suitable horn to the machine (the horn is a rod that presses on the "insert" and inserts it into the plastic), and after adjusting the parameters in the machine, insert the "inserts".


• Speed (mainly in small "inserts").• Speed of exchange between beam and beam for inserting a different "insert".


• With incorrect adjustment, the quality of soldering may be low.• The horn may remove chips from the "insert".• It is difficult to insert more than one "insert" at the same time.• Increased noise.• Incorrect orientation of the machine may damage the "insert" or its screwing.• The foundation is relatively expensive.

Inserting heat "inserts

It is possible to use the same drill that we made for the ultrasonic soldering that we knew. The pressing is done by a heated rod (temperature controlled) whose function is to heat the "insert", and by pressing to insert it into the plastic.


• Reliability and consistency - using a weaker force than that required in ultrasonic welding, allows insertion into thin-walled parts that would be destroyed by ultrasonic use.• Quiet process.• Cheaper equipment.• Possibility of insertion to greater depths.• Better grip to plastic.


• Greater insertion time.

Injection on the "inserts" in the template

With this method, the "inserts" are inserted into the plastic injection mold, and the plastic material is injected on top of the "inserts" (INSERT MOLDING). This method requires semi-automatic work on the machine and a close worker, or alternatively the use of a robot to insert the "inserts" (pays off only in very large quantities). So that the plastic does not get too big of a "thermal market", it is sometimes necessary to heat the "inserts" before injection.


• Stage one creature only.• Only one machine is required.• In most cases, the process is cheaper than using ultrasonic or heat insertion.


• Semi-automatic work depends on the agility of the worker, so the cycle time may change in an unexpected way, which may result in a less stable process.• A worker close to the machine is needed.• In certain materials (for example materials with glass fibers), cracks may occur in the plastic product.

In conclusion

I described only some of the existing methods for inserting metal "inserts" into plastic parts. For each product, the most appropriate method should be adapted. For further reference, you can refer to Insert catalog of the PEM company, in which there is a variety of "inserts", and also the dimensions of the bore to be made for Any "insert" type.

If you want to incorporate "inserts" in your plastic product, you are welcome to contact us.

Committed to the success of your next project !Boaz is a foreigner.

2 views0 comments

Recent Posts

See All


bottom of page