With the rapid development of the take-out delivery industry, the thin-walled plastic boxes used for food packaging are becoming more and more common. In order to reduce product costs, the wall thickness of plastic boxes is also getting thinner and thinner, from the original 1mm wall thickness to 0.4mm today.
At present, the shape of plastic thin-walled boxes are mainly square and round, but also in the square and round internal lattice, used to distinguish the packed meals.
Plastic thin wall container mould require high processing accuracy, so a CMM measure check is required for each machined mold part to confirm that the tolerance of the machined part is within 0.002mm, especially for the core and cavity of the plastic box mold. If the tolerance is more than 0.003mm, you need to do the machining again until it meets the requirement.
1. Runner System：All thin wall container moulds are use hot runner system, the difference is between point gate hot runner and valve gate hot runner.
The top of point gate hot runner is very sharp, after the injection is finished, there will be a dot mark on the product gate location, the advantage is that it is not expensive, while the disadvantage is that the gate location is easy to have the Injection gate wire drawing problem during the injection process.
The front end of valve gate hot runner is flat, after the injection is finished, there is no mark on the surface of the product’s gate, but there is a circle mark, the advantage is that it can improve the injection efficiency, without the injection gate wire drawing problem of point gate hot runner, but the disadvantage is that it is expensive.
Ⅱ：The second point is the cooling system of your stool mould, which needs to do more and finer work in order for it’s cooling effect on each part. Perfecting this will ensure that you get a better product with less cost throughout production because there won’t be any wasted materials or time!
Ⅲ：The third point is the ejector design of the stool mold, the height of the stool is generally quite high, need some long ejector pin in the injection molding completed when the stool from the top of the mold to ensure the separation of the stool and the mold.
In order not to affect the appearance of the stool surface when the ejector, we will put the location of the ejector pin design on the reverse side of the stool reinforcement.
The processing of plastic stool mold is mainly core and cavity.
The processing of the cavity of the stool mold mainly depends on whether the CNC processing tool is long enough to process without shaking the tool. Some stool designs are difficult to process in place at one time, so EDM is also needed. After finishing CNC and EDM, the cavity of the stool mold also needs to arrange deep hole drilling to process the waterway as well as polishing.
The processing of the core of the stool mold can be completed by the conventional CNC processing.
For more accurate processing, we will use five-axis high-speed milling with 20,000r/min to process the parting surface of the stool mold in place at one time to avoid secondary processing.
After finishing the shape processing, the back of the core of the stool mold also needs to process the ejector hole, we usually put it on the five-axis deep hole drill to process, usually the processing time of the ejector hole of a stool mold is 18 hours.
Check if the appearance of the stool mold is all intact.
Check if all sides of the stool mold have been polished well, especially the reinforcement part, if there are burrs on the reinforcement part, it is easy to cause the product surface to be strained when the injection cannot be released normally or when the mold is released.
Check whether the tightness of the thimble of the stool mold is suitable, if the thimble is tight when ejecting, it needs to be readjusted.
Check whether the waterway of the stool mold is smooth, sometimes there will be iron chips stuck in the waterway, causing the waterway of the mold not to be smooth, and affecting the injection of the mold.
At the beginning of injection molding, you need to clean the oil on the mold, spray some mold release agent, the injection pressure is adjusted to 50%, see if the lower gate position is normal, if the first mold hit is uniform injection piece, this is a normal situation. Next, increase the pressure to 75%, at this time the stool product is not fully formed, see if the 4 legs of the stool are about the same size. If the 4 feet are about the same size, that means it is normal, you can continue to increase the pressure until the whole product is molded.
For stool mold, basically every mold factory can do it, as long as there are mold designers and complete processing equipment.
The stroke of CNC equipment is around 800-1000mm, but some rattan moulds will be bigger, so the stroke of CNC equipment needs to be bigger, we usually use 1580x1000mm stroke CNC equipment to make sure all stool moulds can be processed. Also we have 5 axis high speed milling and 5 axis deep hole drilling, all complex stool moulds can be processed and made.
Please contact us using the form below or emailing (email@example.com)