Outline to inline grinding

Outline to inline grinding

I often hear people say that it is difficult to recycle using one crusher per molding machine because of the initial investment.
It is true that a one-by-one system requires an initial investment, but inline crushing solves various problems such as reducing human error and saving labor.

Therefore, Harmo recommends SPC that enables in-line recycling.

Problems and issues

  • The probability of foreign matter contamination is high when grinding in an outline (grinding room).
  • In the case of outline grinding, process of transporting material to grinding room and feeding it into grinding machine requires human labor.
  • In the case of outline grinding, amount of feed is not constant, and feed may exceed capacity of grinding machine and damage grinding machine.
  • Grinding process in outline often uses a high-speed one, so there is a lot of powder and a powder removal process is required. Also, since size of grains is not constant, process of sifting and sorting grains to a constant size is also required. (There are many processes to be recycled.)


  1. By switching to inline grinding, sprues are fed directly from robot into SPC, thus reducing the possibility of contamination by foreign substances. At the same time, it is possible to reduce the number of processes such as transporting to grinding room and feeding.

  2. In inline grinding, robot feeds sprues at a constant molding cycle, so there is no need to feed more than capacity of grinding machine.

  3. In-line grinding allows the use of SPC and eliminates need for dusting and grain sorting processes because there is less powder generation and grain size is constant.

reduce material@2x-1


The staff who used to carry the products to the grinding room and feed them in grinding room can now be assigned to other tasks.
Also, due to long hours of simple work, concentration was lost, and human errors such as foreign matter contamination and crusher damage were eliminated.

With SPC, processes of powder removal and grain sorting are eliminated, and by using a GM, mixing ratio with virgin material can be stabilized (mixing ratio can also be visualized).

Points that could be solved or improved

  • Reduced human error in foreign material contamination and crusher damage.
  • Switch from outline to inline grinding to save manpower.
  • Able to improve productivity by eliminating the processes of dusting and grain sorting.

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Recommend for 
  • It is hard to use recycled materials recycled by conventional crusher
  • Having troubles of appearance defects because of dust
  • Trying to reduce cost by recycling expensive material

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