Gripper design was the crucial factor in solving handling problem
Gripper design was the crucial factor in solving handling problem
Keywords ATM,Grippers, Moulding, Robots
Frequently, when de-mould robots are supplied to a plastics moulding company, it is the design and operation of the gripper which presents the more difficult challenge. Such was the case when Leicester robot manufacturer ATM Automation was approached by CTP Plasro of Mitcham which needed to automate the moulding of a medical product complete with inserts, in a two-cavity tool.
Design of the gripper had to take into account the need for the robot to perform two further functions in addition to the conventional demoulding operation. A weighing/ inspection function had to be incorporated into both the robot program and the design of the gripper fixture to prove the presence of the insert. In addition, CTP Plasro required the robot to place the manually assembled inserts and pre-moulds into the open mould tool. The gripper, therefore, had to comprise both the conventional device to remove the finished mouldings and a second unit to hold the assembled inserts. A critical design parameter for the gripper was the minimal daylight permitted by the constraints of the existing mould tool.
The system was designed such that an operator places metal inserts into moulded preforms and positions them into a fixture designed by ATM as part of the auto-handling package. This part of the fixture then moves under a checking device to ensure that both insert assemblies are present and correctly assembled. The whole system is fully guarded and interlocked for safety to protect both the operator and the process.
At this point, the robot picks the checked inserts from the fixture and positions itself over the tool awaiting completion of the previous mould cycle. When the tool opens the robot moves into the daylight to de-mould the two finished products, re-orientates itself and then loads the inserts into the tool for the next moulding cycle.
On returning to the fixture the robot releases the components to a check weigh platform. This employs weight as an effective quality check and is programmed to give a "good"or "reject" readout, depending on the weight. The operator is then permitted access to remove the product for packing and to position the next inserts for checking. If, for any reason, the operator fails to remove the finished components an arm sweeps them clear before the robot arrives to place the next pair of components for weight checking.
ATM Automation's equipment used by CTP Plasro on the manufacturing of their medical products
This example of automation is one where the use of a robot handling system has ensured consistency in the mould cycle by automated insert loading. It also directly reduces the potential for rejects by identifying faults during the process and handing responsibility back to the operator for correction before the cycle can continue. ATM Automation says that it achieved the CTP Plasro brief in all its strict requirements.
For further information contact Robert Hopper, ATM Automation, UK. Tel: +44 (0) 116 277 3607.
