See Figure 1 for light guide column products of medical therapeutic instruments. Maximum dimensions of product are 56.14 mm *Â 32.80 mm *Â 19.60 mm; average thickness of plastic part is 2.00 mm, material of plastic part is PMMA, shrinkage rate is 1.004, and weight of plastic part is 1.74 grams. Technical requirements for plastic parts are that there should be no defects such as peaking, underfilled injection molding, flow lines, pores, warping deformation, silver streaks, cold material, and jetting lines, and meet ROSH environmental protection requirements.
Tag: Mold exhaust
In mold manufacturing, mold exhaust is a very important link. Mold exhaust can represent quality of overall mold structure to the greatest extent. Even if a good mold does not have a good exhaust, it is impossible to produce a product of stable quality. A good mold should have good airtightness and ensure that gas is freely discharged, rather than being highly compressed.
PC/ABS, polycarbonate and acrylonitrile-butadiene-styrene copolymers and mixtures, are thermoplastic plastics made of polycarbonate and polyacrylonitrile (ABS) alloys. It combines excellent properties of two materials, formability of ABS material and mechanical properties of PC, impact strength, temperature resistance, and ultraviolet (UV) resistance.
When selecting equipment, maximum injection volume of injection molding machine must be greater than the total weight of plastic parts and nozzles, the total injection weight cannot exceed 85% of plasticization volume of injection molding machine.
Temperature Temperature measurement and control are very important in injection molding. Although it is relatively simple to make these measurements, most injection molding machines do not have enough sampling points or lines.On most injection molding machines, temperature is sensed by an electric thermocouple. A thermocouple is basically formed by connecting ends of two different wires. … Continue reading Injection parameters and control
When machine is turned on, hot melt in injection tube of injection molding machine has a long heating time, low melt viscosity, good fluidity, and product is prone to produce sharp edges. After a certain period of time, melt continues to take away heat, resulting in insufficient melt, high viscosity and poor fluidity, which makes product lack of material. After a period of production, gradually increase temperature of tube to solve it.
Weld line, the most common of many defects in injection moulding products. Except for a few very simple injection molded parts, they occur on most injection molded parts (typically in the form of a line or V-groove), especially large complex items that require use of multi-gate molds and inserts. Main reason for weld line is that molten plastic encounters in the cavity when insert, hole, flow rate is inconsistent, or area where filling flow is interrupted, confluence of multiple melts occurs; when gate injection is filled, materials cannot be completely blended.
Exhaust of polycarbonate injection molding is very important in plastic injection molding technology, but it is often overlooked or ignored by many people. During polycarbonate injection molding process, there is a large amount of air in cavity, and injection molding machine can shoot at a speed of bullet. In such a rapid filling process, air in cavity must be quickly discharged. Otherwise it will cause various problems on the product. Main issues are as follows:
Gud Mould 