In modern society, automobile has become the most important means of transportation for people to travel. Its quality not only affects people’s travel quality, but also directly relates to people’s life and property safety. Usually, service life of automotive molding is 600,000 to 800,000 times. In process of design and production of automotive molding, not only technological requirements of automobile body parts should be met, but also problems of mechanical equipment, operation mode, transportation mode, die installation and waste disposal applied in process of design and manufacture should be paid great attention. Following five points should be considered in the design and manufacture of auto parts mold:
(1) Price. In the process of automotive molding design and manufacturing, the first factor to be considered is its price, which will affect final sales of products.
(2) Quality. The safety factor of automobile is usually determined by auto parts mold, so quality of auto parts mold will directly affect sales of products.
(3) Humanization. In process of custom molding for cars design, humanization is also an important factor to be considered, and attention should be paid to its maintenance and repair, so that local replaceability of precision molding can be more reflected. For those parts with high replacement frequency, higher standards should be set in design process, which is very beneficial to both supply and purchase ends. However, humanization of automotive molding in China’s automotive industry is still less considered. It only pays attention to simplification of manufacturing process and production process, which leads to lack of standardization of die parts, so it is more difficult to maintain and repair.
(4) Raw materials. In recent years, our country has a great advantage in material selection of automotive molding manufacturing for mold supplier, usually using alloy steel or alloy cast iron.
(5) Accuracy. In die production, accuracy will directly affect degree of fit between parts after mold assembly and presentation of gap consistency.
Maintenance and repair of automotive molding
Because of bad working environment of auto parts mold, wear and tear of working part, fit part and sliding position often occur in the process of using, even damage. At the same time, due to complex process of die design and manufacturing, high precision, long cycle, high cost and other factors, problems arising from it should be maintained in time in use process, so as to ensure accuracy and improve life. Although maintenance and repair of custom molding for cars is very complicated, there are seven kinds of common faults and maintenance methods as follows:
- (1) Deformation of flanging parts. In process of flanging and shaping, part deformation often occurs, especially in surface parts, which has a great influence on the quality of parts. General solution is to increase material pressure. If it is spring material, method of adding spring can be used, and method of increasing air cushion force is usually used for upper air cushion material. If there is still local deformation after increasing pressure, it is necessary to find out specific problem points and check whether there is a local depression on material surface. At this time, method of welding filler plate can be used; after welding, blank plate can be used with the lower model of die. Noodles are prepared.
- (2) Blade breaking. Blade collapse is one of the most common problems in use of custom molding for cars. If edge of tool is very small, it should be grinded larger by a grinding wheel and welded with corresponding electrodes to ensure that welding is firm and edge is not easy to collapse again.
- (3) Trimming. Blade breaking and hairing mainly occur in drawing, forming and flanging processes. In order to find corresponding position of precision molding according to workpiece, push it forward with oil stone, pay attention to uniform size of rounded corners, and then polish it with fine sandpaper.
- (4) Trimming and punching tape. Abnormal pressure or discharge device of precision molding during trimming or punching results in trimming and punching tape. At this time, we also need to find out corresponding parts of die according to parts. If there is an abnormality in the die unloading plate, we should repair and weld die unloading plate. If there is no problem with die unloading plate, we can check whether tool block of die has phenomenon of broaching.
- (5) Continuous cutting of waste materials. Because operator did not clean up waste in time in production process, resulting in accumulation of waste, and finally under pressure of the upper trimming block caused blade of scrap knife to collapse, resulting in phenomenon of continuous scrap cutting. Method of repairing is similar to that of trimming and cutting edges.
- (6) Burrs. Because of clearance of automotive molding edge, burr of part is too large when trimming, punching and blanking. When gap is large, trimming and punching processes adopt method of fixing die without moving, while blanking processes adopt method of fixing die without changing die. When clearance is small, it should be adjusted according to size of clearance of automotive molding to ensure reasonableness of clearance. For trimming punching die, gap is placed in concave die, while for blanking die, method of enlarging punch should be adopted to ensure that size of parts remains unchanged before and after repair.
- (7) Punching waste clogging. Punching waste is caused by non-smooth waste track, inverted taper of waste track and failure to clean up the waste in time.