The Managing Director of Hubei Xiangze Rivet Manufacturing Co., Ltd. that has a good reputation and influence in drawing screw manufacture industry Mr. Jiang told his trouble when using 2 die 4 blow machine to produce below length of 5mm rivet. The trouble is that clamp adjustment takes more time and energy with less-qualified technique and careless attitude of operator, it will have a warp between die and clamp, punch and cavity die will be destroyed. Even if it is adjusted well, it is not safe. Because adjusting screws on clamp will shake and move due to circular movement, clamp and die will be bumped to ruin, all work has to be started again. Demolishment of die and clamp same as throwing money makes persons regretted. And also adjustment troubles persons and wastes energy, time and money. And Mr. Jiang was very happy to know that the 2 die 3 blow machine of Shixi company with non-clamp design could manufacture drawing screw. He realizes that the production of less length of 5mm screw will be more stable and easier, then he decided to visit Shixi enterprise.
The 2 die 3 blow screw drawing machine Mr. Jiang visited is actually one small side of 2 die 3 blow function
extension. (2 die 4 blow and 4 die 4 blow machine are universally used to manufacture drawing screw in the industry, old method is using more punches and processes to punch the hole of drawing screw.) After mounting P.K.O device (hereinafter called punch knocking out device), the 2 die 3 blow machine varies head forms of parts, shaft parts and shaft parts with hole. The assembly of stripper clamp or stripping type ejector pin mechanism makes stripping of rivet and step parts with hole more convenient. After mounting trimming die device, the 2 die 3 blow can be used to manufacture trimming parts.

If mounted all the above-mentioned structures, the 2 die 3 blow machine will have more functions and wider range of products, which brings additional harvest for users.

Taking the production process of this kind of product as an example (the figure as follows): before for this kind of big head and tine end screw, manufacturers usually use ordinary double heading machine to strike out straights hank and big head part, and then wear to prick end on grinding wheel angle turning machine. But tiny shank brings jumpiness and affects the prick roundness, so that the prick end can easily form multi pyramid surface. If the prick end is not round, it will affect use function of products. So the high level roundness of prick end is required.

Then grind flat end but burrs will appear on prick end and damage inner hole of the matching plastic part and then will affect function of products. The head and shank must not be scraped, which cannot control shaft direction movement made by pressing and rolling of the end prick. And also the prick end can't be processed to flat with pressing and rolling process. The total length can't be controlled easily due to extrusion and distortion, so it is impossible for thread rolling machine and pressing machine to process prick surface.

Manufacturers require better equipment and technology and they find Shixi company. Engineers in Shixi company present the following solution: use 2 die 3 blow machine to head just once, saving investment on flat head grinding machine and prick angle turning machine etc. and reducing the quantity of workers and working procedures.

The specific process is as follows: since screw shank must not be scraped, use nylon wheel as feeding wheel to convey wire rod. Round cutting material (material surface is more flat) is brought to the first die and then two ends of it are made flat by the first punch (meeting the requirement of flat screw bottom) and tail angle turned (offering convenience for prick tail forming of metal); the second punch strikes out prick head on the wire rod in the second die (preparing for head forming finally) and shapes prick tail firstly. The third punch makes out finished product. But stripping of the finished product headed by the third punch is difficult to finish.

Engineers in Shixi analyse that the diameter of tiny tail bottom is only 1.1mm, but the ejector pin length must reach 28mm for knocking out part. So it is too weak for dia.1.1mm ejector pin. Owing to the prick tail is formed by extrusion, it will be fixed tightly in die when it becomes smaller just like nail being nailed in wood. If the ejector pin wants to knock out the part, the resistance force will be very powerful. If knocking the part toughly, the ejector pin will break off.

What should we do?

At this time, engineers in Shixi company think out a solution of mounting stripper device and striking out step-ejector pin. The diameter and the length of smaller ejector pin end are respectively less than 1.1mm and 3mm. Extend round arc to bigger end of§æ6mm, which makes the stress of disjunction and knocking not centralize on combinations of steps, the intensity of breaking and collapse resistance will be strengthened. The §æ1.1mm small end makes the intensity more powerful. After forming, the prick tail is knocked out for 3mm by step-ejector pin and then the semi-finished product is drawn out by the stripping clamp.

In this way, we solve the process problem of this product and reduce equipment variety and quantity, save investment, reduce labor forces and working procedures as well as depress production cost and energy.

Making use of mounting more kinds of devices to extend machine function but not using expensive equipment, manufacturing complex products and solving production problem, Shixi staff have done many such things. For example, using 2 die 3 blow machine with mounting other structures instead of 3 die 3 blow to trial manufacture non head screw and hexagon screw, Shixi staff have gained a stage of success and have been perfecting the technology further; using 2 die 3 blow machine with mounting other structures instead of 3 die 3 blow multi-station machine to manufacture complex flowering hobnail (according to the article of the newsroom: please see the 2nd period of this publication on page 24 " adopting new equipment and technology to produce flowering hobnail" in November 2003.) We believe the machine will influence on the commercial society powerfully in the near future, lower the threshold of investment and technology of using expensive equipment.

On seeing the products Shixi staff have never seen but manufactured by Shixi's 2 die 3 blow machine in the Japanese investment enterprise, they taste that technology is endless and there are more advanced technologies to seek, research and learn. Shixi staff expects that those specialists and technicians using Shixi's 2 die 3 blow machines come out with their experience and improved technology fruits, and also expect them to put forward more opinions and suggestions, which will make this patent machine more consummate.