Material selection and performance requirements for cold heading process of fasteners

Cold heading is widely used in aerospace,automobile and other industrial sectors,mainly used in the processing of bolts,studs,screws,nuts and other fasteners.It has the characteristics of smooth work,high precision,high production rate and easy to realize automation

 

Performance requirements of various parts of multi-station cold heading machine

The connection between crankshaft and machine body and impact connecting rod is made of high wear-resistant alloy copper tile,which has the advantages of large bearing capacity,long service life and low maintenance cost.
(2) The body is made of ductile iron with added alloy,which has high tensile strength and good wear resistance.
(3) Adopt two – stage gear transmission system,it have high transmission efficiency and large transmission torque.
(4) Equipped with pneumatic clutch brake, reduce motor power consumption.
(5)Cutting system adopts guide plate drive cutting rod,guide plate reciprocating motion,cutting force linear transmission,large force stability and good dynamic balance.
(6) The clamping system can be turned over or translated to facilitate the molding process arrangement.
(7) Equipped with frequency conversion speed regulation device,it can be stepless speed regulation in a certain range.

(8)Equipped with fault detection device and safety protection device.Automatically stop the machine in case of equipment failure and provide maximum protection for equipment and tooling

(9) The feeding box is installed with thrust device to improve the feeding accuracy.

(10) Lubricating system oil circuit design is simple and efficient,on the basis of ensuring the circulation of filtration can effectively protect the punch rod and the role of the workpiece.

Selection raw material of workpiece

The raw material must undergo spheroidizing annealing treatment,and the metallographic structure of the material is spherical pearlite.

(2) In order to reduce the tendency of the material to crack as much as possible, to improve the service life of the die,it is also required that the cold-drawn material has the lowest hardness as possible to improve the plasticity.

(3)The precision of raw materials should generally be determined according to the specific requirements of the product and the process,and the multi-station cold heading machine generally requires lower precision for the size reduction and strong shrinkage.

(4)The surface quality of the raw materials requires that the lubricating film is dull and dark, and the surface shall not have any defects such as scratches,folds,cracks,hair-drawing,rust,oxide scale and pits and pitting.
(5) The total thickness of the decarburized layer in the radius direction of the raw material should not exceed 1% of the diameter of the raw material.
(6) In order to ensure the cutting quality of cold forming,the raw material is required to have a hard surface and a soft core.
(7) The raw material should be cold heading test because the deformation resistance increases due to cold hardening.The material is required to be hardened by cold work.

 

      The selection of cold heading forming oil

• It has excellent extreme pressure lubrication performance,high temperature resistance,extreme pressure wear resistance,rust resistance and high temperature oxidation stability.Improvedthe precision and finish of the workpiece,can prevent the mold from sintering,meet the standard parts and non-standard parts of the multi-station forming processing,can be fully competent for cold heading stainless steel workpiece processing.
  (2) The lampblack and “drifting fog” can be reduced to a minimum to meet the strict requirements of multi-die punch nut processing with strong shrinkage die.
  (3)It has good processing performance for products with large deformation, such as hollow,high strength bolts,sleeve,stainless steel hollow,semi-hollow rivets and so on.
  (4) It can effectively protect the punching rod (punching needle) and mold, prolong the service life, reduce the comprehensive cost.
  (5) It has good heat dissipation effect, avoid the workpiece and mold in the process of cold forming local temperature is too high.
  (6) It has high temperature resistance, not easy to produce sludge.Low odor, low smoke,protect the operating environment.
  (7) With a certain rust resistance,can meet the processing process between the rust requirements.
  (8) It can meet the harsh cold heading stainless steel molding processing and large amount of carbon steel molding processing.

 

• Matters needing attention in operation of multi-station cold heading machine

• Precautions before work(1) Check the knife board, cutting tool bar,punch,die and so on should be intact without cracking, properly installed fastening firm.
  (2) After adjusting and cutting off the mechanism, the clearance between the die clamp and the concave die must be checked.It is strictly prohibited to start the equipment without checking.
  (3) In the case of the cutting knife bar has been folded, the roller in the CAM groove must be removed before moving the equipment.
  (4)Carefully check whether the safety protection device of the equipment is intact,to prevent the failure caused by the severe vibration and loosening.
  (5) Check whether the oil circuit of the lubrication and cooling system of the cold heading machine is smooth.If there is any foreign body, it should be cleaned up immediately.When the cold heading forming oil is insufficient, it should be added in time.
  

 

• Do it at work
  (1) Only when the feeding device is disconnected when the equipment is started can the main motor drive the flywheel rotation. Only wait until the flywheel is at full speed before connecting the feeding device. When stopping the equipment,the feeding device should be disconnected before stopping the main motor.
  (2)The slider is not allowed to stop at the “dead” position, such as the slider stops at the “dead” point,only the manual disk moving flywheel method to correct, not allowed to start the equipment.
  (3)The processing of bar or plate material must be clean, material head burr to be worn off,not allowed to have flat material.
  (4) Always pay attention to the working condition of the tray rack, and stop immediately if you find any disorder. When the plate material is processed to the end,the tail should be removed from the plate frame.
  

 

• Do it after work
  (1) Turn off each system of the multi-station cold heading machine in turn,and then cut off the power supply.
  (2)Wipe the cold heading machine clean and apply anti-rust oil on the work surface.
  (3)Record after each run or maintenance.
  (4) When the fault occurs, it is necessary to stop the cold heading of many stations immediately,and find out the cause to eliminate the hidden trouble.

 

• More solutions recommended:Guide shaft is widely used in the chemical industry