The plastic making machines, including Injection Molding for solid units and Blowing Molding for bottles, need a starting-up stage before the normal production status. This starting-up stage will cause additional money cost and time cost. Therefore, manufactuers always to decrease the times of start-up, ie. continuous production for large quantity, to decrease the cost.
The starting-up procedures are desribed in SOPs. The relative parameters should be meet the standards in SOP. Although there are methods how to start up the machines, not all persons can complete this procedure smoothly. The expreienced engineers can largely decrease the time the machines become normal production status. All techinians must be trained before they operate the machines.
To confirm the machines are in the normal production status, a small amount of products must be produced and tested. The beginning products can not meet the quality standard definitely and will be discarded. It is a raw materials waste. Especially, if the color of products change, the waste will be much more.
Moreover, the starting-up stage can not produce any products so it waste the lead time and energy.
Summary, starting-up is a waste but it can not be avoided. What a manufacturer can do is combine products to be made reasonably, try to decrease the times of starting-up, and keep the machines running continously as much as possibly.