Talking Technical P2
Part 2: Quick Mould Clamping Systems
In the second instalment of our series of articles looking at improving productivity in injection moulding, Craig Forrester addresses how investing in Quick Mould Clamping Systems could help manufacturers enhance both profitability and productivity.
Investing in a quick mould clamping system to speed up changeovers can contribute significantly to both productivity and profitability. The latest systems not only speed up mould changes, but also improve machine performance and build operational confidence.
There is a quick mould clamping technique to meet any production or technical requirements. Mechanical, hydraulic or magnetic – systems that provide operational confidence on the production line, improve productivity and yield a rapid return on investment.
The financial benefit of investing in a quick mould clamping system can be readily determined and the payback calculated. This analysis needs to take into account the number of times a mould is changed on a machine, the time currently taken to change moulds and the cost incurred. Comparison can then be made with the quick mould changing system in place. The major benefits are reducing the costly downtime during mould changeovers thereby increasing machine availability for production. Payback times of less than a year frequently result, in some cases payback can be achieved in just a few months from investment in a quick mould clamping system that precisely meets production requirements.
What type of quick mould clamping system is required?
The simplest option is a mechanical system where the mould is held in position by a manual bayonet locking mechanism. This type of system is suitable for injection moulding machines up to around 250 tonne capacity. These are simple, low cost systems that are relatively easy to install. Nearly all injection moulding machines are suitable; the system requires no electric or hydraulic connections.
Existing moulds will require modification; a recess has to be machined into the mould to accept the centring ring in place of the normal register ring.
The complete working surface of the platens remains available for use and any shape of mould can be accommodated.
Hydraulic systems are suitable for any size of injection moulding machine up to the highest capacity. Single acting or double acting hydraulic clamps, conforming to EUROMAP requirements, are available for the automatic clamping of moulds on both existing and new machines. The clamps operate on a steel backplate, which is securely bolted to each mould. Moulds require a bit more modification than in the manual bayonet locking system and the backplate dimensions are critical to ensure clamping effectiveness. The backplates have to be left permanently attached to each mould, adding to the overall cost of this type of clamping system.
Magnetic systems are suitable for all moulding machines. One of the key advantages of magnetic systems is that no modification to moulds is required and the use of backplates can be eliminated. The system will readily accept any shape of mould. Magnetic systems are quick to install, fast in operation and virtually maintenance free, having no moving parts.
The latest development in magnetic clamping systems has improved their ease of use and provides enhanced data flow to bolster confidence in operation. The technology actively manages and secures the clamping operation, providing direct control of clamping/declamping, guiding the operator through the process sequence with a direct display of the clamping force. The operator has access at all times to additional information e.g. plate temperature (both fixed and moving sides), identification of the moulds on the machine, clamping force for each mould half and mould movement detection. The platens stay magnetised even under power failure adding to the safety of the system. These user-friendly features make magnetic clamping systems extremely reliable, while the increased data flow to the operator improves confidence.
Magnetic, hydraulic or mechanical, the choice of a quick mould clamping system will depend on the specific operating parameters of any moulding shop but the benefits are clear and will significantly improve both productivity and profitability.