In the production of metal containers, there are many processes that belong to the stamping process. Over the years, due to the safety issues of stamping, incalculable property losses have been caused and many workers have become disabled. According to incomplete statistics, in recent years, among the enterprises in the metal container industry in China, an average of 5 or more persons with disabilities in each company is caused by insecurity in stamping.
Crank presses are commonly used for punching, and most of them are open, and the structure is difficult to change. However, we can introduce a safe design concept when designing a die, and we can solve this problem relatively easily.
Stamping dies are the main technical equipment for stamping processing. Stamping parts are the relative movement of upper and lower dies. During the processing, due to the constant separation between the upper and lower
Molds, if the operator's fingers continue to enter or stay in the mold closed area, it will pose a serious threat to their personal safety.
First, the safety requirements of the mold design (a), the main parts of the mold, role and safety requirements 1, the working part (bump).
The working part is a working part that directly forms the blank, and therefore, it is a key part of the mold. The convex die is not only sophisticated but also complex. It should meet the following requirements:
(1) It should have sufficient strength and cannot be broken or destroyed during the stamping process;
(2) Appropriate requirements shall be placed on its materials and heat treatment to prevent hardness and brittle fracture.
2, positioning components.
The positioning component is a component that determines the installation position of the blank, and includes a positioning pin (plate), a material-blocking pin (plate), a guide pin, a guide plate, a distance-distal side cutter, a lateral pressure regulator, and the like. When designing the positioning parts, the operation should be considered convenient. There should not be too much positioning, and the position should be easy to observe. It is better to use the positions of forward pushing, positioning of outer contour and positioning of guiding pins.
3, pressing, unloading and discharging parts.
The pressure parts have blank holders, press plates, etc. The blank holders can press the edge of the drawn billet to prevent the billet from arching under the effect of tangential pressure to form wrinkles. The role of the press board is to prevent the billet from moving and bouncing. The role of ejector and ejector plate is to facilitate the out-of-stock and cleanup of waste. They are supported by air springs, rubber, and air-cushion push rods on the equipment and can be moved up and down. The ejector parts should have sufficient ejector force in the design and the movement must be limited. The stripper plate should be as small as possible in the closed area or in the operating position to mill the empty hand slot. The exposed stripper plate should be provided with a protective plate around to prevent the fingers from penetrating or entering the foreign body. The exposed surface edges should be blunt.
4, guide parts (guide posts and guide sleeve).
Guide posts and guide bushes are the most widely used guides. Its role is to ensure that the male and female dies have a precise fit clearance during the stamping operation. Therefore, the gap between the guide pillar and the guide sleeve should be smaller than the blanking gap. The guide post is located in the lower die holder, to ensure that the upper end face of the guide post is at least 5 to 10 mm above the top of the upper formwork plate when the dead point is at the stroke. The guide posts should be located away from the module and the platen, so that the operator's arm does not have to feed material over the guide posts.
5, support and hold parts.
It includes upper and lower stencils, die shanks, male and female mold fixing plates, backing plates, stoppers, and the like. The upper and lower formworks are the basic parts of the die, and other various parts are respectively fixed and fixed on the top. The plane size of the template, especially the front-rear direction, should be compatible with the workpieces. Too large or too small are not conducive to operation.
Some molds (blank blanking, punching type molds) need to be set under the mold frame for the convenience of shipping. At this time, the backing plate is preferably screwed together with the template. The thickness of the two backing plates should be absolutely equal. The spacing of the backing plate is based on the outgoing parts, not too large, so as to avoid cracking the template.
6, fastening parts It includes screws, nuts, springs, pins, washers, etc., are generally used standard parts. The amount of standard parts of the stamping die is larger, and the need for fastening and elastic ejection should be ensured when the design is selected, and the fasteners are prevented from being exposed at the surface operating position, so as to prevent bruising and obstruction of operation.
(b) The safety aspects of the mold design should be as simple as possible to ensure the convenience of feeding, sizing, dispensing, and cleaning of the waste. For the processing of small parts, it is forbidden that the operator's fingers, wrists, or other parts of the body protrude into the mold area; for the processing of large parts, if the operator must hand-operate in the mold, the scope of the mold should be reduced as much as possible. Minimize the time for a part of the body to stay in the mold, and make sure the scope of the die danger zone is equipped with the necessary protective measures and devices.
The various parts on the mold should have sufficient strength and rigidity to prevent damage and deformation during use. The fastening parts should have anti-loose measures to avoid accidental injury to the operator.
Do not allow the phenomenon of waste or workpiece flying during processing, affecting the operator's attention or even injuring the operator. In addition, it is necessary to avoid the burrs from cutting parts to cut the hand. Operators are not allowed to have excessive movement when performing stamping operations, to avoid losing the stable posture of the body, and not to allow excessive and difficult movement during the operation. Should try to avoid the strong noise and vibration during stamping. The mold design should mark the weight of the mold on the general drawing to facilitate installation and ensure safety. More than 20 kilograms of parts processing should have lifting handling measures to reduce labor intensity. When assembling and disassembling the mold parts, it should be convenient and safe, avoiding the possibility of cutting hands or cutting hands; the molds should be easily disassembled and stored.
In short, even subtle problems in the mold can affect safety. Only the analysis of specific problems in each operation can raise safety considerations in the mold.
Second, mold safety design research examples
Safe operation is an important practical problem often encountered in stamping work. Stamping design should fully consider the personal safety of the stamping operation, equipment safety and die safety in order to eliminate hidden accidents. According to the practical experience of the barrel makers, the following measures are mainly applied in the design.
(A) feeding direction
1, using standard mold, left hand feed.
In the stamping operation, people are accustomed to feeding with right hand. However, due to the standard formwork commonly used for punching die, the guide posts of the diagonal guide post formworks are left in front and right in the back. When the stamping workman feeds with the right hand, the strips are sent to the end, because the spirit is highly concentrated. By punching the parts, the right hand is easily flushed between the upper and lower molds of the peripheral interface of the die work. If left-handed feed, the strips are sent to the end, because the left guide bar blocks the left hand's continuous feed, ensuring personal safety. Therefore, die design, as much as possible use diagonal guide pillar mold.
2. Auxiliary safety guide posts or baffles are added to the post-column formwork.
If the die structure of the guide post is to be selected for other reasons such as the process (Fig. 1), an auxiliary safety guide for left-hand feed must be provided. In addition, a safety baffle (Figure 2) can also be provided. This type of safety baffle is more suitable for the post-or middle mold bases of the two guide posts.
(II) Guide to Blanking Dies
In order to ensure the safe use of the blanking die, the orientation of the upper and lower die must be taken into account when designing the die.
1. The use of a standard mold base should also consider the convex-mould counterparts of single-sided punching guides. Otherwise, it can easily cause squeezing and cause unsafeness in the process of die use - abnormal damage to the mold. Therefore, the punch edge of a single-sided punching operation can be made into a cutting edge (Figure 3).
This form can reduce punching force when punching thin stock.
2, in the case of mold structure, the best use of * back punch (Figure 4), also known as the distance between the side edge punch. This punch has a * back, punching absolute guarantee that the punch normally enters the die mouth. Therefore, the die will not be damaged due to the mouth.
3, the edge of the board blanking (cutting angle, cutting mouth) punching hole from the edge near the mold structure must be simple and then set the guide. For the edge punch punch punch "back style" is good, male and female die clearance to take one-way value (Figure 5), Z value can be determined according to the type of material and thickness check table.
4. For the punching of holes near the edge of the plate, it is necessary to design the front guide column, which is convenient for the mold, and also prevents the rinsing.
(3) Positioning of blanking and bending parts
During the punching process, the parts are strictly prevented from manual positioning and temporary positioning of tools and thrust positioning. Specially punching thinner plates is even more dangerous (Figure 6). The overall dimensions of the same workpiece or each component punched in the same batch cannot be exactly the same, so it is best to use elastic positioning. Hedges are in the form of (Figure 7).
The shape of the curved flat blank is adopted (Figure 8). The longitudinal direction of the spring sheet is the same as the bending direction.
Ningbo Metal Sharing Supply Chain Management Co., Ltd
