What is the difference between extrusion molding and injection molding of hollow board?

What is the difference between extrusion molding and injection molding of hollow board? What is the difference between extrusion molding and injection molding of hollow board? Recently, many readers have sent private messages to consult me about this issue. The kindness is difficult. So, the content sharing on hollow boards in this issue will mainly focus on this topic. #hollow board# In the current market, our common hollow panels are generally extrusion molded, and injection molded hollow panels are rare. The extruded hollow board allows the raw material to be plasticized between the extruder barrel and the screw while being pushed forward by the screw and continuously passed through the head to make various sections or semi-products. This process technology, the production process is continuous, can extrude any length of hollow board, the productivity is very high, the mold is simple, the size can be accurately grasped, the manufacturing and maintenance are convenient, and it has the advantages of low investment and high efficiency. In the injection-molded hollow plate, the plastic is heated to a certain temperature by an injection molding machine, the plastic is melted into a liquid, injected into a sealed mold cavity, and molded after cooling.It can produce all kinds of hollow board products with complicated sound insulation, the molding structure size is more accurate, the surface quality is better, and it can be standardized, standardized, and serialized, but the mold is expensive, the equipment is expensive, and the investment is huge.

How to select and verify the accuracy and stability of injection molding machine?

Choice of power mode for injection molding machine2002 years ago in the production of injection molding machine is essentially the traditional quantitative pump injection molding machine, the type injection molding machine is quantitative pump using ac generators to provide power injection molding, injection molding machine in action when push valve hydraulic oil pump rotation action, implement open, lock mould, plastic, injection, shot before and after moving, thimble, before and after pulling shoot glue of pumping action.When the injection molding machine without action or need to pressure flow is small, the system through the relief valve will be redundant hydraulic oil back into the tank, that is to say, the full load motor and oil pump works, the equipment needed for energy distribution is controlled by the overflow valves, resulting in injection molding process, most of the energy is to "flow" go in vain.Since 2004, variable pump injection molding machine began to appear on the injection molding machine market stage.Variable pump injection molding machine mostly USES proportional variable pump (screw pump, plunger pump, gear pump) as the driving element, belongs to the typical positive displacement speed regulation system.The system is composed of load-sensitive proportional variable pump, proportional relief valve, proportional speed regulating valve, pressure feedback valve, flow feedback valve and so on, which has more obvious energy-saving effect compared with the driving quantitative pump injection molding machine.After 2008, widely used in injection molding machine servo energy-saving injection molding machine manufacturing, the system consists of dc motor, controller, and other components of the feedback system, oil pump, truly a "need to how much energy system power supply", servo motor can do servo closed-loop control, than traditional quantitative pump injection molding machine and energy consumption of variable pump injection molding machine.Generally speaking, the servo energy saving injection molding machine compared to variable pump injection molding machine energy saving 10-30%, than the traditional quantitative pump injection machine energy saving 30-70%.The all-electric injection molding machine developed in recent years can separate each action of the injection molding machine, and each reciprocating action is controlled by a servo motor, which can achieve lower power consumption.Figure compares the energy consumption of different injection molding machinesTherefore, generally speaking, the injection molding machine produced by injection molding machine manufacturers, from the consideration of energy consumption can choose quantitative pump injection molding machine, variable pump injection molding machine, servo energy saving injection molding machine and full electric injection molding machine.At present, the domestic injection molding machine power configuration is the same, choose the same system of the injection molding factory basic not big difference, difference between the single biggest reason, however, are mostly concentrated on the issue of using dynamic size, more power can provide higher parameter selection range and clamping force control, but the injection molding machine configuration and mechanical failure is more likely to lead to leakage, and needs more layers of tubing and machinery with rigidity, injection molding machine cost part will also rise.Selection of injection pressure for injection molding machineInjection pressure of injection molding machine Pi=P*A*s/AoP = System working pressure (MPa)A = Effective cross-sectional area of injection piston (cm2)S = Number of injection cylinders (generally 2)Ao= Cross-sectional area of screw or feed cylinder plunger (Cm2)From the above formula can be seen, the product needs higher injection pressure, such as some engineering materials, the optimal method is to increase the system pressure, or increase the area of the cylinder and increase the number of injection cylinder (this is very small), and is to reduce the diameter of screw.Therefore, when the injection molding machine manufacturers give us the choice of screw injection molding machine, large diameter screw injection pressure are lower, suitable for general plastic processing;The smaller the screw diameter, the greater the injection pressure, the more suitable for processing engineering plastics;When we need to use more injection pressure, injection cylinder diameter must be larger to meet the requirements;Single cylinder injection pressure is not as high as double cylinder injection pressure.Usually, because of the space limit of injection molding machine, injection piston rod diameter can not be unlimited increase, screw diameter can not unlimited decrease, more injection cylinder in injection balance can not be guaranteed, so generally can only choose 2 injection cylinder, so the normal standard injection molding machine injection pressure to reach 250MPa has been very large.If processing products and materials need higher injection pressure, more often through increasing the system pressure to achieve, before the quantitative pump injection molding machine USES 140MPa oil pump, now injection molding machine generally USES 175MPa oil pump, foreign injection molding machine more use is 220MPa system pressure oil pump.The servo motor of the all-electric injection molding machine can provide more than 450MPa injection pressure, which has a natural advantage in precision molding.In the selection of injection molding machine, engineering materials and precision parts as much as possible to choose high injection pressure injection molding machine.Injection rate and injection rate selectionThe injection speed of the injection molding machine is the distance that the screw moves forward per second in cm/ SEC: S=Q/AThat is: injection speed = pump discharge ÷ injection cylinder effective areaS: Injection velocity cm/ SECA: Injection cylinder effective area cm2Q: Pump discharge volume CC/REV (ml /rev)We usually say 300 fire rate, 500 fire rate, 1000 fire rate injection molding machine, generally refers to this speed.As can be seen from the formula, when the diameter of the oil cylinder is small, the injection speed is larger; when the displacement of the oil pump is large, the injection speed is larger.On what products do we have more urgent requirements for injection molding speed?When the product is thinner, we require a higher injection rate to fill the mold as quickly as possible.To improve the injection speed, on the one hand, it is to increase the pump displacement, on the other hand, it is to reduce the diameter of the cylinder.Many customers in the choice of injection molding machine, injection molding machine manufacturers are required to increase the pump displacement of one or two levels, is generally considered for this.And increase cylinder diameter has an obvious side effects, the injection pressure will decrease because of the increasing oil cylinder diameter, when we produce thin-walled products, in order to overcome the material flow resistance need higher injection pressure, but in order to improve the filling speed to reduce the injection pressure, the method of most is not desirable, the general plastic this method is not recommended.Injection rate refers to the plastic capacity injected by the injection molding machine into the air per second. The unit is Cm3 / SEC:V=S*AV: Injection rate cm3/ SECS: Injection velocity cm/ SECA: The cross-sectional area of the screw or barrel is cm2The injection rate is a unit volume representation of how much material can be injected per second, and the larger the number, the more you can inject into the mold.In some thick-wall heavy products, this parameter is very meaningful, for general products and thin-wall products, injection speed can better represent the performance of injection molding machine.Injection molding machine machinery and lubrication systemThe injection molding machine system is generally composed of a frame, three plates, Corinth column, injection molding system, ejector system, mold adjusting system, etc. The domestic injection molding machine frame is generally made of welded steel, three plates are cast iron, Corinth column, mold adjusting gear, ejector mechanism and so on are basically purchased and assembled from professional manufacturers.Quality assured injection molding machine manufacturers, many of its suppliers are supplied by the same several manufacturers, the difference in quality is not big.The parts designed and manufactured by ourselves or manufactured by external partners are mainly on the rack, three big plates and oil circuit plates, etc., which are directly controlled by the injection molding machine manufacturer for their quality and cost.By comparing several injection molding machines of similar models and different manufacturers, we can know which one has the higher production cost.The clamping mechanism of injection molding machine and the rack shooting table account for 90% of the total weight of the machine. When the machine weight of one injection molding machine manufacturer is heavier than that of another injection molding machine manufacturer of similar models, the cost of this manufacturer is naturally higher than that of another manufacturer.As an industrial product, heavier equipment means a more stable foundation and a more reliable working life, which is qualitatively different from crafts.So, when we buy the injection molding machine, do not ignore the weight of the injection molding machine itself this index.

How to choose an injection molding machine?Do you know these methods?

Injection molding machine procurement project is not a small investment projects;Buying too big an injection molding machine is wasteful, but buying too small is not appropriate.Therefore, choosing an injection molding machine that meets the needs of its own products has become the most concerned content of every buyer.Small make up the integration of multiple information, edit a relatively simple and practical matters needing attention to choose and buy, hope to give plastic injection processing plant customers and friends a little good advice and help!One, according to the injection molding machine specificationsAccording to the weight of injection products in each region, the injection volume of injection molding machine should be calculated1) When the injection molding product is made of polystyrene (PS), the injection molding machine shall have the injection volume of Wps:Wps = (product weight + total gate system) ÷ (0.75 ~ 0.9)That is, Wps = (1.3 ~ 1.1)× (product weight + total gate system weight)2) If the product is other plastics (named as X plastics), following the above method, calculate the theoretical injection volume of such plastics as Wx:Wx = (1.3 ~ 1.1) × (product weight + total gate system weight)However, Wx cannot be simply used to determine the injection volume of the injection molding machine. Wps value must be changed. The conversion formula is as follows:The Wps = Wx present pWhere P is the specific gravity of the plastic3) Another relatively simple method is to determine whether the jet weight meets the following requirements:W = 0.75 ~ 0.8 * Wmax * PW: The maximum weight of the actual molded product (including the weight of the glue mouth)Wmax: Maximum PS injection weight of model screwP: The proportion of raw materialsAs long as the product gram weight is less than the calculated W, that's ok.Taking HMD128M6-B screw molding PP material as an example, the maximum injection weight of PS theory is 239g, namely Wmax = 239.PP material density is 0.9, that is, P = 0.9.W = 0.75*239*0.9 = 161(g)That is, as long as the product weight is less than 161g of PP material products 128M6B screw can meet the requirements.2. Calculate the clamping force P according to the vertical projection area of the injection product on the template (head plate or two plates)Mode-locking force = mode-locking force constant × projected area of productSo P is Kp times sType in theP-clamping force (T)S- Vertical projection area of the product on the template (Cm2)Kp- modulus locking force constant (T /cm2),Kp values listed in the following table (Table 1)Kp (For injection moulding of more precise products)3. Determine the internal spacing size of the tie rod (guide column) of the injection molding machine based on the outer contour size of the mold;The latter is greater than the former.4. The mold opening stroke of the injection molding machine is determined by the product height;The latter should be more than twice the former.5. Other minor factors1) The volumetric modulus of the non-molding machine should be appropriate to the height of your mold;2) Thimble stroke, top output;3) Process factors.Two, according to injection screw selectionStandard screw selectionGeneral injection molding machine has A.B.C three - gear screw, part has four - gear.The same type A screw injection pressure is the largest, generally can reach 190~210MPA or so, gram weight is the smallest.C screw injection pressure is the minimum, generally around 120~130MPA, gram weight is the maximum.B type or C type is generally chosen.Only in the production of raw materials PE,PP,ABS products thick case, can be considered to use C screw.A screw must be selected for the following products:The wall thickness is below 1mm.PC,ABS, nylon, steel and other engineering plastics, products complex, high precision.Some products require side gelling due to design and are over 80 times longer (the length of the gelling point to the end of the product and the thickness of the product).2. Special screw selection1) PC special stainless steel or electroplating screw, some models can choose standard A screw plating.PC screw, thread gradient small, high injection pressure2) SPVC, UPVC granular materialSPVC headless electroplating screw and UPVC headless electroplating screw are selected. In addition, for products with high requirements, a strong air cooling device should be installed on the material barrel.3)PA6,PA66 without glass fiberNylon special screw, part of the nylon material can be used standard screw, but the cutting speed is not as fast as the special screw.4) PA6, PA66 and glass fiberUnder 15%, it can be considered that ordinary double alloy screw with ordinary barrel, 15%-30% special double alloy screw with double alloy barrel, 30%-50% special full hard double alloy screw with full hard double alloy barrel.Double alloy screw5)PC color mixing and partial thin-wall PP color mixingSpecial color mixing screw, more than 268 models equipped with color mixing mixing head6) Small gram heavy transparent PC productsSmall gram weight transparent PC product is to point to gram weight is less than standard A screw shoot glue gram weight 20%.It is suggested to select special small screw and shorten the length to diameter ratio of screw to 20-22:1 at the same time.Prevent PC material yellow, dark, insufficient whiteness.

What is the language of the PLC and touch panel?

 PLC and touch panel English and Chinese, or other customized language

Is there complete machine include mould and other auxiliary equipment ?

Yes ,what we are provide is the complete system and you will no need spend, a lot to find the suitable water chiller and color mixer...etc.

How about quality control in your factory?

“ Quality is the key point, do what customers needs”