Cup preform pre-forming extrusion die design

In our daily work and life, the cups that are often encountered are mostly cup-shaped parts with the same circumferential wall thickness and the same thickness as the cup, as shown in Figure 1 and the cup with the boss shown in Figure 2. Shaped parts. These parts are generally made by cold-rolled sheets through blanking and multiple draws. Sometimes, due to the special performance requirements, cup-shaped parts with unequal wall thickness are often encountered, as shown in Figure 3.


Figure 1 Cup-shaped parts


Figure 2 Cupped part with boss


Figure 3 unequal wall thickness cup parts


1. Double stud 2. Lock nut 3. Sleeve 4. Die pad 5. Base plate 6. Pull rod

7. Punch 8. Upper die plate 9. Upper die holder 10. Pad 11. Guide cover

12.Adjust the pad 13. Die die 14. Press template 15. Positioning seat

16. Backing plate 17. Top rod 18. Beam 19. Lower mold base

Process analysis

The unequal wall thickness of the cup-shaped part is characterized by a thin wall of the mouth, and the wall of the root is thick, the thickness of the bottom and the circumferential wall are different, and the thickness of the bottom is large. If such parts cannot be formed by cold-rolled steel sheets, the following methods are generally used to manufacture such parts:

(1) Machining is performed by a machine tool using a solid core bar. Although the processing method can ensure the dimensional accuracy requirements of the parts, the mechanical properties of the different parts are required. At the same time, the utilization rate of the materials is low, the production cost is high, and the requirements for mass production cannot be met.

(2) Hot extrusion→thinning and deep drawing This method uses a bar material and then extrudes into a cup-shaped blank by a hot extrusion process. Finally, it is drawn into a cup shape with a thick bottom and a thin wall thickness by a thin drawing process. Pieces. The parts produced by this method not only have high yield, dimensional accuracy, product quality and mechanical properties can meet the requirements of the parts. At the same time, the material utilization rate is high, the parts production cost is low, and the requirements for mass production can be met.

According to the above analysis, it was decided to adopt the hot extrusion→thinning and deep drawing process.

2. Mold structure and working process

The thinning drawing die is designed according to the conventional design. The following mainly introduces the design of the extrusion die.

(1) The hot extrusion die of the mold structure design is shown in Fig. 4.

(2) Features of the mold 1 The mold adopts a universal mold base, which has strong versatility and convenient mold processing and manufacture. 2 The mold is equipped with a lower top material mechanism to facilitate the ejection of the blank. It is especially suitable for use on hydraulic presses without a lower tank unit. 3 The matching precision between the die and the pad adopts the transition fit of H7/m6. 4 The matching precision between the lower mold base and the positioning seat adopts the transition fit of H7/m6. 5Adjust the pad to control the thickness of the bottom of the blank. 6 The mold structure is simple, and the installation and adjustment are convenient.

(3) The working process of the mold puts the heated blank into the cavity of the die 13, and the upper part moves downward under the action of the movable beam of the machine tool, the punch starts to contact the blank, and is gradually pressed into the blank, with The upper mold portion continues downward, and the punch 7 is gradually pressed into the rough material to gradually increase, and when the upper mold portion is moved downward to a certain position, the hot extrusion forming of the part is completed. Thereafter, the upper mold portion is ascended, the punch 7 is pulled out from the formed cup blank, and the cup blank is left in the die 13, at which time the upper mold portion continues to ascend, the tie rod 6 and the sleeve 3 and the stud are studs. 1 Pull the beam 18 upwards. The beam ejects the formed cup blank from the die 13 through the ejector rod 17 and the bottom plate 5, completing a working cycle. The hot-extruded blank is then subjected to subsequent processing by thinning, extension, machining, etc., and finally becomes the required part.

3. Problems in production

(1) The thickness of the bottom of the blank is ensured by adjusting the thickness of the adjustment pad.

(2) Strictly control the heating temperature of the blank before hot extrusion to avoid excessive or too low temperature.

(3) Strictly control the wall thickness difference of the hot extruded blank. If the wall thickness difference of the blank is too large, it is difficult to correct it in the subsequent thinning and deep drawing.

(4) When hot extrusion, try to use a larger degree of deformation to reduce the number of times of thinning and drawing.

(5) When hot extrusion, the surface of the mold needs to be coated with a lubricant. In order to facilitate demolding, some small pieces of wood or charcoal are usually placed on the upper end surface of the bar placed in the die.

(6) Before each shift, the mold must be preheated. The preheating temperature is 250 to 300 °C.

Chemical intermediates and chemical raw materials

Guanidine nitrate is a white crystalline solid. Soluble in water. Takes some effort to ignite but once ignited it burns with increasing vigor as the fire progresses. If contaminated with combustible materials it accelerates their burning. Prolonged exposure to fire or heat may result in an explosion. Produces toxic oxides of nitrogen during combustion.

Guanidine nitrate is a strong organic base existing primarily as guanidium ions at physiological pH. It is found in the urine as a normal product of protein metabolism. It is also used in laboratory research as a protein denaturant. 

Chemical Intermediate

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