CLAMPING SYSTEM: MANUAL, TOGGLE, HYDRAULIC, HYDRO-MECHANICAL & T BAR LESS CLAMPING
The function of clamping unite is to clamp the injection mould. The clamping pressure is set more there the injection pressure, so that the mould doesn’t open during plastic melt injection.
Manual Clamping:
Manual clamping in only seen in the case of manual or hand injection moulding machine or some time in pneumatic injection moulding machine. The proper clamping is depending on the skill of the operator. The clamping force is direct and not measured. The position of the sprue with respect to nozzle axis is critical. The injection of the part from the mould is difficult.
Toggle Type Clamping:
To toggle is mechanical device to amplify force. In a moulding machine, which consist of two bars joined, together and to end with a pivot. The end of one bar is attached to a stationary platen, in the other end of a second bar is attached to movable platen. When the mould is opened, the toggle is in the shape of a V. when the pressure is applied to the pivot, the two bars for a straight line.
Advantages:
- Low cost and lower horse power needed to done.
- Positive plan of the mould
Disadvantage:
- Do not read the plan force
- Clamping is more difficult
- Higher maintenance has lubricant is provided
Hydraulic Clamping:
A clamping unit actuated by hydraulic cylinder, which is directly connected to the moving, closed the mould; in this case RAM of hydraulic system is attached to moving platen. There are two halves in hydraulic cylinder, which is actually inlet and outlet of oil.
When oil goes to the cylinder with pressure, oil pushes the RAM to forward direction by which moving platen moves and mould closed. And when oil comes from the cylinder the RAM comeback and mould is open.
Advantages:
- Clamps speed easily controlled and support at any point
- Direct read out of clamp force
- Easy adjustment of clamped force and easy mode set up
- Low maintenance has part is self lubricated
Disadvantage:
- It is a higher cost and more expensive then toggle system
- Noun positive clamp
Hydro-Mechanical:
This clamping system is combination of toggle and hydraulic clamping system to move the toggle a hydraulic cylinder is operated.
Tie Bar less Clamping:
Tie bar less clamping system is basically hydraulic clamping system without any tie bar, the platen is moved on a rail system.
The main advantage of the system there is no limitation of mould platen size. Has there is no tie bar so the mould dimension is not so important. Also mounting of the mould is easy and it is very useful when products eject from the mould is manual. Advantage of tie bar lower machines.
- Much larger mould mounting area
- Larger stroke compared to the toggle type machines
- Full machine capacity can be utilised
- Smaller machine can mould larger component
- Saves floor space
- Saves electrical energy because of reduction in the size of machine
- Has the capacity to radius weight of the molded component because tie bar stretching is not there
- Machine becomes very flexible for future modification
- Easy assess to mould cavity’s because of the absence of the tie bars
- Robotic arn movement becomes easy
- Fewer moving parts so lesser wear and tear so longer life for machines
- Lower lubrication required
- Removal of mould plates much simple
- Greater stability
