Optimisation of the Changeover Procedure on a 20 MN Pressing Line

Meeting delivery deadlines is of great importance in companies today. Customers demand extremely short delivery times, which are difficult to achieve in practice. This problem can be mitigated or almost completely resolved by introducing proper scheduling , where it is important to schedule using the most optimal method possible. They proposed the best example of changeover procedure optimisation, whereby the pressing procedure changeover time was reduced by more than 60% – ** from three to four hours they ** shortened the changeover procedure to ** one to one and a half hours**. They researched all the necessary literature that was essential for optimising the line.

Problem

Meeting delivery deadlines is of great importance in companies today. Customers demand extremely short delivery times, which are difficult to achieve in practice. This leads to a vicious circle: orders accumulate in factories and warehouses are often filled to full capacity, production cannot fulfil everything, urgent orders appear in between causing even greater chaos, and the situation seems hopeless.

Solution and Method

This problem can be mitigated or almost completely resolved by introducing proper scheduling, where it is important to schedule using the most optimal method possible. However, since problems cannot always be resolved even with the proper scheduling method, it often happens that multiple tool and process changeovers must be performed on the machine. Such problems can be resolved through ** optimisation of tool changeovers** or ** procedures**.

Not every position or line in a production facility is suited to the same optimisation method by which they will optimise the changeover, because machines differ in designation and production competences, therefore optimisations must be carried out individually for each machine separately and even then in several different variants. In the diploma thesis, they presented three possible methods of **optimising the pressing procedure changeover **, which is carried out on the 20 MN pressing line, where, according to customer order requirements, casting material stocks and scheduling urgency of orders, cyclical changeovers of the seamless tube or bar pressing procedure are performed.

The objectives they set were fully achieved.

Results

They proposed the best example of changeover procedure optimisation, whereby the pressing procedure changeover time was reduced by more than 60% – ** from three to four hours** they ** shortened the changeover procedure** to ** one to one and a half hours. They researched all the necessary literature that was essential for optimising the line. Based on the fact that after optimisation the piercing mandrel and ram are no longer dismantled, we can also confirm the objective regarding reduction of press wear and consequently press accuracy, as it is no longer necessary to wait for the intermediate member and ram to heat up to ** operating temperature and be tightened to final torque, as was required before optimisation, since this is already done.

Likewise, we can fully confirm the hypotheses of the diploma thesis, as with the selected changeover procedure optimisation they reduced non-productive time during pressing procedure changeover, consequently ** reduced press wear** due to multiple changeovers and cooling and reheating of segments, and ** improved accuracy of pressed products, because in the selected best optimisation they provided that the piercing mandrel and ram always remain assembled during the changeover procedure and are no longer replaced. Based on all the presented material that they processed in the diploma thesis, we conclude that the best and most favourable changeover procedure optimisation option is the third proposed option, which shortens the pressing procedure changeover time by three hours, which means a good 60% of the changeover time before optimisation, and is also ** the most cost-effective – just under 1,000 EUR.

The management of Impol did not decide on any of the optimisation options, as many parts of the 20 MN pressing line for pressing seamless tubes are worn out and fatigued, therefore the future development plan of the Tube Mill includes procurement of a new pressing line for production of seamless tubes. The existing one should only press bars and profiles, which should in future be cut to shorter lengths and not coiled into rings, as scrap in ring production is several times higher. In the diploma thesis, they proved that line optimisation can be carried out.

They presented the best possible solution, however we doubt that with such a future plan as is currently set for the production process P. C. P.

Tube Mill at Impol, any financial investment in the worn-out line would be economically viable.