SMC/BMC mould pressing shapes in the process, need notices to control good “3 mainly dot ” , also be main 3 essential factor. Namely pressure of mould pressing temperature, mould pressing and control of mould pressing time.

Mould pressing temperature is the mould temperature that when mould pressing shapes, sets, parameter of this one craft determined a pattern to the stock inside modular antrum conduct heat condition, have conclusive effect to the melt of stock, flow and solidify process. SMC/BMC moulding expects the temperature change case in mould pressing process is more complex, as a result of plastic the undesirable conductor that is heat, stock center and brim begin level difference in temperature in what shape bigger, this will bring about solidify cross-linking to react the layer of inside and outside in stock is not to begin at the same time. Surface layer makings because be heated in the past solidify and form hard housing layer, and lining makings is in later because solidify systole gets the limitation of exterior incrustation layer, often put inside the surface layer that causes mould pressing goods remains presses stress, and lining contains remains to pull stress, the existence of leftover stress can cause goods warp, craze and intensity to drop. Because this adopts measure to endeavor to reduce the difference in temperature of inside and outside of the stock inside modular antrum, eliminating inhomogenous solidify is one of fundamental conditions that acquire high quality product. The mould pressing temperature that SMC/BMC moulding expects depends on the radiative peak temperature of solidify system and solidify rate, take the temperature limits with solidify peak a bit a bit lower temperature to be limits of its solidify temperature normally, be 135-170 ℃ about commonly and decide through the experiment. The system with solidify rapid rate takes the temperature that on the low side nods, the system with solidify slow rate takes on the high side some temperature. Shape the upper limit that temperature range takes when thin wall goods, shape large wall goods is desirable the floor level of temperature limits, but shape when the thin wall product with very old deepness, because technological process is long,be solidify of the stock in avoiding process of going from place to place, also should take the floor of temperature limits. Below the premise that does not damage product strength and other property index, raise mould pressing temperature appropriately, shape to shortening cycle and improve product quality advantageous. Mould pressing temperature is too low not only tall, fluidity differs the stock viscosity after melt, and be hard to undertake adequately as a result of cross-linking reaction, make product strength not high thereby, the exterior appears when lacklustre, drawing of patterns sticking to mould and top go out be out of shape. 　　 2, control of mould pressing pressure

Mould pressing pressure uses mould pressing intensity of pressure normally (MPa) will express, namely the total force that hydraulic press of glass reinforced plastics brings to bear on to go up in the mould and mould antrum is compared in what use the umbriferous area that controls direction to go up. Mould pressing pressure shapes in mould pressing the action in the process, be make the mould closes cheek by jowl and make stock is added close, and stimulative frit makings flows and small element content volatilizes inside balance model antrum the pressure of a generation. The mould pressing with big compressibility expects, because make its are added close when should waste more energy, when shaping consequently, need to use higher mould pressing intensity of pressure, reason mould pressing comes loose shape stuff is more expensive than the pressure of semifinished product of mould pressing material, and makings of SMC/BMC mould pressing compares mould pressing again the pressure of farinaceous makings is high. Viscosity of mould pressing melt the stock with rapid rate of tall, cross-linking, and process form complex, wall when the goods with thin, deepness or large area, because need to overcome resistance of greater going from place to place,just can make modular antrum cram, consequently need uses higher mould pressing pressure. Because high mould pressing temperature can make cross-linking reaction is quickened, bring about frit to expect viscosity is rapid thereby heighten, reason needs to use high mould pressing pressure to cooperate to it. Although high mould pressing pressure has make goods density increases, shape shrinkage is reduced, make rapid flow charge a pattern, overcome strut and prevent air hole to appear wait for a series of advantages. But mould pressing pressure crosses congress to lower mould service life, increase hydraulic press power to use up, increase stress of the remains inside goods. When because this machines plastic pattern of hot solid sex,suppress is tasted, use more press beforehand, warm-up, proper raise mould pressing temperature to wait, use high mould pressing pressure in order to avoid. If raise warm-up temperature or lengthen warm-up time of impropriety to be caused,be in warm-up process already partial solidify fluidity is reduced, cannot reduce mould pressing pressure to should assure antrum of stock cram model instead with higher mould pressing pressure not only. 　　 3, control of mould pressing time

Mould pressing time also says to reduce dwell time of moulding heat preservation. Be after showing the mould closes completely or hind after deflate shuts a model, arrive between mould open, stock is inside the model the time of be heated solidify. Mould pressing time is in shape the action in the process basically is make win modular antrum figure shape content has enough time to finish solidify. Solidify is to show hot solid sex is plastic the formation of structure of the bodily form when shaping process, solidify process is the process that cross-linking reaction has in light of the essence that reacts from chemistry. But complete ” does not mean the “ solidify on craft cross-linking reaction already undertook after all, namely all active that can attend cross-linking base the group already attended reaction entirely. This one term is to show cross-linking reaction already had appropriate rate on craft, the integrated physics of goods is mechanical function or other and special designation function already reached expectant target. Apparent, the cross-linking of goods is spent achieve 100 ℃ impossibly and the phenomenon that solidify degree can exceed 100 ℃ to exceed cross-linking level of requirement of complete solidify place normally however calls “ to cross ripe ” , call “ to owe ripe ” conversely. Mould pressing time decides the solidify rate that expects with SMC/BMC moulding really, temperature of the structure of thick, mould, mould pressing mixes the appearance of goods and wall the discretion of mould pressing pressure, and press beforehand, warm-up and when shaping whether the element of the many sided such as exhaust is concerned, in all in these elements with wall of mould pressing temperature, goods thick with warm-up condition the influence to mould pressing time is remarkable. Because appropriate warm-up condition can accelerate stock inside modular antrum warm up the process of process and cram model antrum, be helpful for shortening consequently mould pressing time, the ply that time of the mould pressing when raising mould pressing temperature shortens subsequently and increases goods wall should extend mould pressing time accordingly. When mould pressing temperature and mould pressing pressure are constant mould pressing time becomes the crucial factor that decides goods function, mould pressing time passes short colophony cannot complete, goods owes solidify ripe mechanical performance is consequently poor, the exterior lacks luster, easy occurrence warp is mixed after drawing of patterns be out of shape etc. Lengthen mould pressing time to be able to overcome the weakness of above not only appropriately, still can make of goods shape to shrinkage is reduced and make function of its hear resistance, intensity and dielectric protecties all rise somewhat. But lengthen mould pressing time overly to be able to make products too familiar again, produce loss of efficiency, specific power consumption to increase not only and because excessive cross-linking astringe is led,can increase can cause the internal stress with the larger generation between colophony and filling, often also make goods surface hair dark bubbly, serious when burst of meeting occurrence goods.