The various reasons why the mold produces flying edges

- Apr 23, 2019-

What is the reason for the flying edge? The reasons and elements of the production of flying edges are multifaceted and complex. Let me give you a few answers.
brief introduction
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What's a flying edge? Flying edge, also known as Overflow, edge, Burr, etc., most of them occur in the location of the mold, such as the split surface of the moving mold and static mold, the sliding part of the slide, the gap of the veneer, and the pore of the top rod. The fly-edge is largely due to the failure of the mold or platform locking force. In general, due to the influence of various factors, it is impossible for the plastic parts to produce flying edges.
Flying edge generation
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However, how to reduce the flying edge and improve the quality of plastic parts is an important research topic in the field of plastic molding and precision injection molding. The specific causes of flying edge may be caused by the following:
1. The highest locking force of the machine platform is not enough. Moulding machine hinge wear or Moulding cylinder sealing elements wear drop oil or return, resulting in reduced mold force. If the heating system is out of control and the actual temperature is too high, the thermocouple and heating ring should be checked for any problems.
(1) The mold cavity distribution is not balanced or the degree of parallelism is not enough to cause the force imbalance and cause the local flying edge. The local dissatisfaction should be placed in the center of quality symmetry as far as possible without affecting the integrity of the parts.
(2) When the force of the moving member and sliding core in the mold is unbalanced, the flying edge will be caused.
(3) When the mold exhaust gas is poor, the compressed air will cause the split surface of the mold to expand and a flying edge will appear. A good exhaust system should be set up, or the exhaust ditch should be dug on the split surface.
2. If the mobility of plastics is too large, or if too much lubricant is added, the pressure, speed, temperature, etc. should be reduced appropriately, and the use of lubricants should be reduced. If necessary, low-mobility plastics should be selected.
3. Processing, adjustment:
(1) If the temperature, pressure and speed set are too high, segmented injection shall be used. Injection time, holding time, and excessive feed will cause flying edges.
(2) When adjusting, the mold lock machine hinge is not straight, or when opening and locking, the mold adjusting nut will often move, resulting in insufficient lock force to appear flying edges.
(3) The parallelism between the adjustment head and the diode is not enough or the system pressure of the adjustment is too large.
4. The reasons for repeated dissatisfaction with flying edges and parts:
(1) When the size of plastic raw materials is uneven, the amount of additives will be uncertain.
(2) The wear and tear of the superglue head, superglue ring and superglue gasket of the screw is too large, so that the melt may cause flying edges or dissatisfaction between the screw and the cylinder and the reflux.
(3) The cooling system of the inlet fails to adjust the feed.
(4) The amount of injection adjusted by the cartridge is insufficient, that is, if the buffer pad is too small, it will cause more time and less time to shoot the material and there will be dissatisfaction with flying edges or parts.
Flying Edge Solution
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The first is the reason for the flying edge: 1. The mold type(PL) sliding surface does not match; 2, exit pressure is too high; 3, the offset of the injection machine; 4, insufficient lock touch.
Problems related to molds: 1, mold split surface PL, sliding match surface, die pin, pad, etc.. The gaps between the various slots that make up the mold, if the material is flowing, it becomes a flying edge. The flying edge is wedge-shaped. There is a tendency to gradually become larger; 2, the elimination of the flying edge of the product is generally based on the principle of repairing the mold, because the forming conditions are not set, the flying edge should be used to reduce the temperature of the cylinder. Set parameters in the direction of decreasing material fluidity by reducing mold temperature and dropping the rate of output. However, the use of this should be aware of the internal stress that can cause the product residual.
Solution: 1. Instant: lower the injection pressure and lower the temperature of the heating cylinder. Reduce the rate of emission; 2, short-term: the surface of the flying edge of the mold to grind; 3, long-term: mold use hard steel material.
Due to the difference in materials: 1. Because of the good fluidity of materials, flying edges are also easy to produce, so the mold type surface should be strictly; 2, crystalline materials at the time of melting due to low viscosity. In particular, it is necessary to have a strict mold type surface.
Reference matters: 1. It should be noted that excessive pressure on the mold will also produce flying edges, between the split surfaces, and the foreign body will not only damage the mold, but also produce flying edges; 2, mold materials usually use materials such as S50C(Japanese JJS standard equivalent to domestic 50 # steel) to use HRC30 pre-hardened special steel, it is difficult to produce flying edges on the sub-surface.