The project is plastic because of its exceedingly good character -- high strenth, heat-resisting, impulse withstand, fight ageing to wait and be applied extensively at industrial spare parts to reach all sorts of crust to make on. But plastic product craze also is a problem that your poll is fond of, the cause that causes craze involves a mould, shape the respect such as stress of craft, plastic material, environment. Today
The day debates the reason of plastic product craze and solution;
One, craze reason shallow analyse and improve a proposal
Different craze account can cause different craze type, according to the craze situation that in developing a process actually, encounters, phenomenon of plastic products craze has 4 kinds of cases normally:
Craze of 1. drawing of patterns, plastic products from mould emergence when direct craze, reason of this kind of craze and consequence are easier beforehand appraise;
2. dependability checks craze, if decline,check, the environment checks, after screwy test is finished local craze or occurrence crackle;
3. assembles craze, the product is assembling the craze in the process;
4. applies craze, the product is in after setting period of time or craze appears in use process, this kind of craze often is forecasted hard, and the sequential likelihood of generation is annihilative.
Above circumstance of a few kinds of craze, have internal cause, also have external cause, also have same reason; Be aimed at above problem, we analyse the main factor that affects product craze in the round from the following respects respectively;
2, the influence of products plan
Large wide gap of 1. product wall is too big, local shrink is serious;
The product when 2. is designed is local bone too feeble, cannot bear big wallop;
3. is overall design intensity is too weak, reinforcement is too little;
Pointed horn of 4. product interior is too much, glue goes to be not arranged when noting model, had better transfer with round horn, reduce the craze risk that stress concentrates;
3, the influence that the mould designs
1. passes into glue mouth big
2. runner design distributings unreasonable, form frit wiring easily, around frit wiring product strength is the weakest;
Design of 3. cooling system is unreasonable, local super-cooling or overheat generation stress are contractive;
Rake of 4. drawing of patterns is insufficient
Design of 5. model antrum is bad (produce in-house stress to center)
6. exhaust is insufficient
7. product top goes out lopsided, easy when the top goes out local suffer mechanical responsiveness to send craze;
8. mould surface is too rough
4, the influence of the craft that note model
1. material is metric and overmuch
2. colophony temperature is too low
3. mould temperature is too low
4. shoots a pressure exorbitant, too small metropolis affects product strength, pressure too because stress is great,congress creates close from runner product structure and become fragile, too small conference creates pressure slacken of intensity of line of joint of product flow extreme, the product is likewise easy craze, the proposal analyses data to adjust according to modular shedding;
5. is shot maintain pressure too big
6. shoots a time to grow too
7. top gives rate too fast or too slow
5, the influence of plastic raw material
1. material contains volatile
The mixture with 2. different qualitative capable person is tie-in.
3. material not stoving
4. mix into expects into water mouth too much
The exterior craft when finishing is opposite 5. the product has corrode action, time became long can produce crackle;
Influencing factor of craze of the product that note model is more, want integration analysis consideration, a lot of elements are restricted each other, products plan should shift to an earlier date to be analysed together with mould design, reasonable accept or reject, solve a problem, promotion character;
