Insert Moulding

Although insert moulding is not a new technology, finding a single supplier to manufacture the complete system for you is often a challenge.

We were asked recently by a client to do just that based on our vast experience in moulding automation along with our skills in manufacturing high quality parts feeding solutions. They have a plastic mouldi
ng with 2 threaded inserts and they needed a complete insert moulding cell in order to fully automate the production.

The small brass inserts are 6mm diameter, with an 8mm ‘top hat’ flange and a length of approximately 10mm.

The system requirements were such that, 2 inserts were required every 35 seconds, at a determined pitch for the finished moulding. The feed rate requirements for this system were not high and the bowl was tooled in stainless steel on a cast aluminium top. The insert orientation requirement was for the ‘top hat’ flange feature to be uppermost.

The natural choice for this application was a 300mm diameter vibratory bowl feeder used in conjunction with a vibratory linear feeder, to offer a production buffer and adequate feeding. By utilising our standard range of vibratory drives for both the bowl and linear feeders we were able to manufacture a high quality feeding solution for use with this system.

The design of the bowl feeder tooling was relatively simple and the concept relied upon the natural centre of gravity of the insert when hanging on the ‘top hat’ flange. The insert will naturally ‘swing’ with the knurled diameter hanging downwards when supported under the flange. This enable inserts traveling either flange leading or flange trailing to be ‘swung’ into the out-feed tooling.
This assessment of the natural balance of a part always forms the basis of the tooling design for all bowl feeding applications. We are faced with many different components, each having their own distinct characteristics, many components we are familiar with through our extensive experience in providing feeding solutions and some will require initial trials to ascertain the best method for manufacturing the orientation tooling.

These initial decisions will also allow us to specify which of our standard range of feeding solutions best suit the application according to size, feed rate and complexity of orientation tooling required. From this our team of bowl tooling engineers can manufacture each bowl to the bespoke requirements of the component and the client. 

 A further challenge for this application was the pitch that the inserts needed to be presented to the injection moulding tool. It was essential that this position was repeatable and dependable and ultimately undisturbed by the vibration of the linear feeder.

Our extensive experience in automated solutions enabled us to design a robust solution for this problem. A three position, pneumatically operated escapement unit was a perfect solution. 2 of the three positions allow for inserts to enter the tooling plate within pockets provided. The 3rd position allows for an undisturbed position and also ensures that trailing parts on the linear feeder are not affected when the inserts are collected by the robot.

The robust nature of all of our designs ensures that every piece of equipment is suitable for harsh repetitive environments. The escapement slides are located and mounted on re-circulating linear bearing rails, all with definitive end stop positions and dampers for the removal of inertia. Each and every position is verified with sensors and part presence is checked at each loading cycle.

The further requirements for the system were for the inserts to be raised from the escapement to enable collection by a Cartesian robot, design and manufacture of robot end of arm tooling, out-feed chute, guarding requirements and machine framework. The robotic handling and integration elements of this project draw on our core skills in the injection moulding industry for which we have manufactured in excess of 250 systems worldwide.

The end of arm tooling mounted on the robot was not only needed to grip the inserts, but also to collect the finished moulded part from the mould tool and deliver it to the out-feed area. With the added complexity of needing to rotate the end of arm tooling 90 degrees on the robot, the result was a relatively intricate tooling arrangement. It was ensured during the design of the system that accurate location was provided during collection of the inserts by use of locator pins. This ensured that the inserts were repeatedly positioned every time and the accuracy of the robot was not the limiting factor.

The entire system was capable of de-moulding the finished product with a Cartesian style robot, loading inserts into the mould tool, feeding sorting and orientating inserts prior to loading and being fully integrated with an existing Injection Mould machine at our client’s premises.

This project not only displayed a number of the different skills and capabilities that we possess but also provided a single source for our client in order that all of the system requirements could be fulfilled by the one supplier.

              

                                                                                                                   

Unit 3a Swannington Road,
Cottage Lane Industrial Estate,
BroughtonAstley, Leicestershire,
LE9 6TU. United Kingdom