注塑模具mold-005.doc

BossThe boss shape used to install a screw to parts.e.g. for a joint of a plastics modelCavityThe gap generated where a part is molded in the mold.It sometimes refers to the concave part of the mold and usually is processed on the cavity plate.Clamping Force / Closing ForceClamping force is put on a mold to keep the mold closed against the pressure of the injected molten plastics.Clamping begins with confirming clamp up of the mold after the mold closing process finishes and continues until clamping force reaches the official capacity.The maximum force to clamp a mold is used to specify a molding machine, and represents the size of a molding machine. Closing force is exerted from full mold opening to clamp up of the movable side of the mold to the fixed side.A mold is kept closed under low pressure until the completion to avoid damage to the mold.Closing force is usually divided into two steps: it uses low pressure in the early phase of closing and becomes higher immediately before the completion.The closing speed is divided into two levels, also, to avoid damaging a mold if the mold is closed rapidly.Also, if foreign matter is left inside the mold, clamping force can avoid damage to the mold. The process of closing and clamping is as follows:High speed closing Slow closing (Mold protection circuit starts) Clamping (pressure rising) Clamping Time / Closing TimeClamping time refers to the time from when a mold is completely closed until when clamping force is pressurizing.Clamping time does not change on one molding machine. Closing time refers to the time from when a mold starts closing until when it is completely closed.Closing time varies depending on the movement amount or the shape (thickness) of a mold.A mold is closed at high speed at first, and then at low speed immediately before a slide core or an angular pin starts moving. Therefore, adjust closing time at the position where the speed changes or in the low speed zone.The shorter the closing time is, the shorter the molding cycle time can be; however, clamping must be done securely rather than shortening its time, because incomplete clamping will cause molding defects.CopolymerizationThe reaction in which more than two molecules of one chemical material are combined to be made into a new chemical material with several fold molecules.In other words, more than two materials are combined and react to make a material of properties different from those of the original.Clamps / SpacerThe setup tools used to install cavity adaptor plate and core adaptor plate to the movable / fixed plates of the molding machine.The spacer functions as a bottom plate for setting a clamp, and the clamp holds down the cavity adaptor plate and the core adaptor plate with a bolt.CrackA breaking on parts caused by inner stress, external shock, or environmental impact.DegassingDegassing is the process to release the water and air contained in a molding material, the gas generated during molding, and the air existing in the mold before molding. Molding large or thick parts without degassing may cause swelling or bubbles on the surface, aggravating the appearance.Degassing is usually done by making a ditch on the mold or using a hole on the ejector pin.In the figure below, the land is used to do degassing and air venting.Draft AngleThe gradient made on the cavity or the core to make removal of parts from the mold smoother.Draft angle normally requires 1 - 2 degrees, but it depends on the material and molding shape, or whether a texture process (the process to make the surface a little rough) is done.In injection molding, because molten plastics will shrink after molding, make as small a draft angle as possible on the cavity side, and a large angle on the core (insert) side. Because crystalline plastics has high mold shrinkage, it shrinks into the inside of the mold on the cavity side, which makes removal smooth, whereas it adheres to the mold on the core (insert) side, which makes removal difficult. Therefore, to make a draft angle, you will need to take the adhesion to the core (insert)