1、 Lack of material
Nachdem das geschmolzene Material in den Formhohlraum eingetreten ist, ist es nicht vollständig gefüllt, was zu einem Mangel an Kunststoffteilen führt.
Ursachen und Gegenmaßnahmen:
(1)Improper selection of equipment: when selecting equipment, the amount of melt glue on the machine must be greater than the amount of melt glue on the products, and the weight of Spritzgussteile can only account for 85% of the total amount of melt glue on the machine.
(2) Insufficient material supply: if there is bridging phenomenon at the feeding port, the screw injection stroke can be increased appropriately to increase the material supply.
(3) Poor fluidity of raw materials: improve the retention defects of the mold pouring system, reasonably set the pouring position, expand the gate, flow channel and the size of the injection gate, and use a larger nozzle to properly increase the temperature of raw materials.
(4) Unreasonable design of gating system: when designing gating system, attention should be paid to gate balance, which is proportional to the weight of plastic parts in the mold cavity and gate size. It is that each mold cavity can be filled at the same time. The gate position should be selected at the original wall position, or the design scheme of balanced layout of runner can be adopted.
(5) Schlechter Schimmelauspuff: Überprüfen Sie, ob ein kalter Materialhohlraum vorhanden ist oder ob die Position korrekt ist. Für die Form mit tiefem Hohlraum sind am unteren Einspritzteil eine Auslassnut und ein Entlüftungsloch anzubringen. Die Entlüftungsnut mit einer Tiefe von 0. 02-0. 04 mm und einer Breite von 5-11 mm kann auf der Schließfläche geöffnet werden. Das Entlüftungsloch muss an der endgültigen Füllposition des Formhohlraums eingestellt werden.
(6) In the aspect of process operation, we can improve the mold temperature, reduce the injection speed, reduce the resistance of the gating system, and reduce the closing force.
(7) Die Formtemperatur ist zu niedrig: Die Form muss vor dem Start - auf die vom Prozess geforderte Temperatur vorgewärmt werden. Wenn die Temperatur der Form nicht ansteigt, prüfen Sie, ob die Gestaltung des Formwasserkanals angemessen ist.
(8) Insufficient injection pressure: the injection pressure and the length of the die are close to a positive proportion. The injection pressure is too small, the length of the die is short, and the cavity filling is not enough. Therefore, the injection pressure can be increased by slowing down the injection forward speed and extending the injection time appropriately.
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2、 Deformation
Da die innere Schrumpfung des Produkts inkonsistent ist, ist die innere Spannung unterschiedlich und die Verformung wird verursacht.
Ursachen und Gegenmaßnahmen:
(1) Unausgeglichene molekulare Orientierung: Um die durch unterschiedliche molekulare Orientierungen verursachte Verformung zu minimieren, sollten Bedingungen geschaffen werden, um die Verformung zu verringern. Fließorientierung und Entspannung der Orientierungsspannung: Die effektivste Methode ist die Reduzierung der Kunststofftemperatur und der Formtemperatur. Bei Verwendung dieser Methode ist es besser, sie mit der Wärmebehandlung von Kunststoffteilen zu kombinieren, da sonst der Effekt der Verringerung des Unterschieds der molekularen Orientierung oft nur von kurzer Dauer ist -. Das Behandlungsverfahren besteht darin, dass die Orientierungsspannung im Kunststoffteil weitgehend beseitigt werden kann, wenn das Kunststoffteil entformt und für einen bestimmten Zeitraum auf einer hohen Temperatur gehalten und dann langsam auf Raumtemperatur abgekühlt wird.
(2) Improper cooling: when designing the structure of plastic parts, the section thickness of each part should be consistent as much as possible, and the plastic parts must be kept in the mold for sufficient cooling setting time. For the design of mold cooling system, it must be noted that the cooling pipe should be set in the position where the temperature is easy to rise and the heat is relatively concentrated. For those parts which are easy to cool, slow cooling should be carried out as far as possible to make the cooling of all parts of the plastic parts balanced.
(3) the first mock exam is not enough. The edges are not light. The plastic parts have a slope when designing the mold. If a product & #39;s uneven slope is distorted, the product will be rough and rough. In the design and acceptance of the mold, the angle of the supporting film and the smoothness of the edge should be considered.
(4) Cooling time: when the vulcanized plastic is filled into the mold cavity, there must be cooling time. The cooling time will cause the product ejection deformation. The product is not sufficiently cooled. When ejection, the product will also deform if it is relatively soft. If it is too slow, the product will completely cool in the mold cavity and ejection has no elasticity. The hardtop product will also deform, so the cooling time should be set appropriately.
(5) Injection process: injection process, pressure, speed, time, location, can make the product deformation. When setting the parameters, it should be considered repeatedly. When adjusting the machine, adjust the parameters slowly in 1 unit to obtain the best parameters.
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3、 Phimosis
Wenn die Kunststoffschmelze von der Trennfläche aus der Form gedrückt wird. Ein Blitz entsteht, wenn der Hohlraum eine Folie erzeugt.
Ursachen und Gegenmaßnahmen:
(1) Insufficient clamping force: when the clamping force of the injection molding machine is too low to maintain the clamping force of the mold, the flashing will occur. It is necessary to adjust the area of the plastic part and the molding pressure to see whether they exceed the rated clamping force of the equipment and improve the clamping force. If they exceed the limit, the machine with large tonnage can be replaced, and the injection pressure, mold temperature, injection speed, time and position can also be adjusted from the process of adjusting the machine.
(2) Material temperature is too high: the plastic temperature is too high, resulting in the melt viscosity is too low and the material overflows between the templates. You can manually spray glue to observe the fluidity of the raw materials. You should properly reduce the material temperature, and at the same time, try to precisely process the mold to reduce the mold gap.
(3) Mold defect: mold defect is the main cause of overflow flash. Carefully check whether there are sundries in the mold closing surface and guide pillar hole, resulting in the mold not being closed. Whether there is balance between the mold templates, whether there is bending deformation, and whether the opening distance of the template is adjusted to the correct position according to the thickness of the mold. Whether the lock module surface is damaged, whether the pull rod is deformed unevenly, and whether the exhaust slot hole is too large and too deep. If the formwork deformation is caused during forming, the supporting formwork or thickened formwork shall be added to prevent the formwork deformation.
(4) Improper control of process conditions: the injection speed is too fast, the injection time is too long, the injection pressure is not evenly distributed in the mold cavity, the filling speed is not balanced, and the feeding amount is too much, resulting in flash and drape. Taking corresponding measures to reduce the filling speed, especially the speed close to the completion of filling, the injection pressure and the holding pressure, can reduce the required clamping force and avoid using too low
