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Commentary Narrative:
The customer manufactures a patch, which is injected with a controlled drug, which is then placed in a pouch. The pouches are packed 1000 to a box. Because it is controlled drug there can be no error in counting. The existing system proved to be unreliable producing frequent mis counts and required manual recounting and checking of all product.
Somex were requested to submit a design proposal for a new packing machine that would eliminate counting errors and handle rejects all at a cycle time of 0.7 seconds per pouch. Pouches were produced in 2 sizes 75mm x 100mm & 100mm x 125mm.
A reliable sensor for counting each pouch was easily sourced, however product handling and control was fundamental to a satisfactory solution. Working closely with the customer we proposed the use of servo driven conveyer belts capable of giving rapid acceleration and de acceleration. Prior to passing under a counting sensor the pouches passed through a thickness sensor and reject mechanism to ensure 2 pouches were not lying on top of each other. After counting, the pouches are passed to a slower running belt, which overlapped the pouches, a process called ‘shingling’. After shingling 50 pouches the belt is accelerated forward to create a gap between the next count of 50. In the event of a mis count it is now possible to reject 50 rather than 1000 as previously.
For packing, the boxes increment as the pouches are inserted, 20 batches of 50 are packed prior to a box indexing. The box loading station is equipped with vibration and side clamps to assist with settling the pouches.
Change between product sizes is designed to be fast and efficient. Primarily using fixed hard stops the changeover by the operator is complete in 10 minutes. Installed early 2007 there has been no recorded incidence of a miscount.
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