The material used for the product was thermosetting epoxy resin which requires special technical conditions for processing and, in addition, gold-plated inserts of 1 mm in diameter and 4 mm in length needed to be fitted in the mould - 4 pieces for each product. A key aspect was process stability, which was the most important guiding principle for moulding epoxy resin-based materials. If the process had been unstable and manufacturing had had no constant cycle time, the number of rejects would have increased exponentially, resulting in a considerable loss due to the integrated components and the high cost of the material.
Challenges to be addressed:
• process stability,
• efficient fitting of small inserts into a 170°C mould,
• efficient post-processing of the product.
In the current market context, complete automation of product manufacturing would have required a considerable investment. Due to the completely unpredictable market environment and the high volatility of energy prices, our company decided for the in-house development of a semi-automated manufacturing process.
When designing the mould, we considered that while the injection moulding machine is running, the operator tending the machine should be able to keep working, preparing the next moulding process by fitting the inserts in the mould plate. We tackled this by making a so-called ejector plate; while one was being processed in the mould, the operator prepared the others for manufacturing. Another challenge was that the mould had to be kept at the specified 170°C temperature, which also required heating outside the mould, while ensuring that the operator did not come into physical contact with the heated mould plate as it would have resulted in an injury at work. A magnetic switch was used to provide heat for the mould plate and could be turned on and off at the press of a button by the operator when replacing the ejector plates.
To fit the inserts, a simple hand gripper was used to pick up the pins from the pre-sorting tray and insert them into the ejector plate with a simple pin guide, fitting the inserts into the heated mould in a single step. The mould had four cavities so 16 tiny pins had to be inserted per cycle, in this case every 58 seconds. With the help of the pre-sorting tray and the insertion tool, the process took 20 to 25 seconds.
After each thermoset manufacturing process, the products came out of the mould with burrs on them and the next step was post-processing and deburring. We have developed a deburring and punching machine in-house. At the end of each cycle, the products were removed from the mould and kept on the sprue. In the next step, the ejector plate was replaced in the mould and a new cycle was started. Inserts were fitted for the next cycle and the remaining 30 seconds were used to insert the previously removed, semi-finished product to the puncher where the sprue is removed and product is deburred in a single step. These cost-effective solutions enabled us to be competitive towards our customer (a full-scale automation solution would have made the hourly machine rate considerably more expensive), make steady deliveries with defect-free quality, enhancing our reputation and aiming for long-term future cooperation.
Our company is available to manufacture products with significant added technical value and our technical team is ready to develop and implement the most efficient and stable manufacturing processes specifically for the product at hand.