Procedure & Steps

Material import

Raw materials are imported from certificated Korean supplier Posco manufacturd by DongBang Steel Co.,Ltd. When the materials come to Chia Chen, they are classified and stored by specification of each.


  • 30 heading machines in total imported from Taiwan and classified as one die one blows, two dies two blows, three dies three blows, and the production ability of screw from M2-M16 (diameter 2mm - 16mm and length 4mm - 350mm)
  • The average production capacity of a month is 120 tons.

Thread forming 

36 thread forming machines imported from Taiwan include:

  • 5 ones for automatic systematically inserting washer before thread forming for screw M2-M8
  • 20 ones for automatic thread forming of screw M2-M16
  • 2 tail cutting machines for splitting (according to customer's requirement)
  • 10 head splitting machines for creating slot drive of screw

Monthly production capacity:150 tons


  • 24 maching, 6 drilling machines, 2 flat pressing machines, 2 milling machines.
  • Machining is process used for complicated and accurately required parts of a screw that can't be formed in the heading process. The flat pressing machine is to straighten the screws (usually for part of the axle). Milling Machine is used to create roughness glossiness of screw.

Heat treatment

  • A row of heat treatment machine imported from Taiwan with monthly production capacity about 190 tons. This is used to achieve the hardness and tensile strength requirement stipulated by the customer.
  • Heat treating including heating, quenching, cooling and tempering processes cause changes in the structure of the screw. The changes affect several aspects of a screw like hardness, ductility, toughness and wear resistance. Screws once are heated to the required temperature and kept at this temperature for a certain period. A great increase in hardness is achieved after they are quenched in water, oil, which rapidly brings down the temperature. Tempering is required to relieve the internal stress of the screws to make them less brittle and more ductile and improve its toughness. Not every screw undergoes heat treatment. This is used to achieve the strength requirement stipulated by the customer.

Surface treatment/Plating 

  • 2 rows of plating imported from Taiwan includes 2
  • 2 rows of ZINC Plating and 1 row of dacromet, involving: 2 centrifugal machines, 2 drying machines, 6 dehydrogenation machines (dehydrogenation for strengthening screw) with yearly production capacity 160 tons. They are able to do ZINC-B, -K, -C with thickness >=8µ. The salt spray testing of ZINC-B results in maximum up to 48 hours. The salt spray testing of ZINC-K, -C result in maximum up to 72 hours.
  • Dacromet includes 2 sand blasting machines, 2 centrifugal machines and one row of rinsing. The salt spray testing of dacromet results in maximum up to 400 hours.


  • 2 screw inspection machines, 1 automatic packing machine and 8 packing lines
  • 2 screw inspection machines imported from Taiwan, used to eliminate all kinds NG goods, with daily production capacity 1 ton
  • 1 automatic packing machine with automatic weighing and packing at high accuracy and able to eliminate NG goods.   

Stocking & Shipment

  • The finished products are lined up and classified by customers.
  • The products are packed and stocked by requirement of customers (customization)
  • The products shall be weighed again before shipping.
  • Delivery always comes on time .