for cavity arrangement. According to the geometric structure characteristics, dimensional precision requirements, batch size, mold manufacturing difficulty, mold cost and so on, the number of cavities and their arrangement are determined.
The quality control of bottle embryo during production depends on the control degree of bottle embryo to avoid scratching during transportation. Determine the gating system (shape, position, size of main gating, sub-gating and gate) and the exhaust system (method of exhaust, location, size of exhaust tank).
Select the ejection mode (top rod, pipe jacking, push plate, combined ejection), determine the side concave treatment method, core pulling mode. If the customer provides the Decuma bottle embryo injection machine, confirm that the bottle embryo injection machine allows the mold size to be long, wide, high and injection weight;
There are also injection molding machine positioning ring diameter, nozzle ball head radius, the position and size of the ejection rod. Different bottle embryo injection molding machine parameters are different. The other is to determine whether the thickness of the bottle mold meets the injection molding machine * mold thickness.
Easy to ignore is the ejection distance, this must be confirmed clearly. Attention: at the beginning of injection molding, the material is not allowed to fill the cavity immediately, should gradually increase the injection volume.
Adjust the relevant equipment and injection process parameters according to the actual condition of the product during injection molding. The volume of the bottle can be calculated by dividing its weight by its specific gravity. Because the weight of the bottle is fixed, its volume is also fixed.
Amplify the bottle model with Scale to compensate for the cooling shrinkage of the bottle. The shrinkage rate of PET plastics is 0.70.8. We generally set the magnification factor to 1 0 75. Using the function of UG Boolean operation, the bottle solid model is converted into die cavity.
The design of guide column, guide sleeve hole, cooling channel and exhaust groove is made by using the basic characteristics. Must be discharged immediately to obtain a full bottle sample.
Mature process conditions:
1. effective mold temperature control: mold cavity, mold core can achieve rapid cooling, to have refrigeration water, and water hardness is appropriate, anti-scaling, anti-blocking.
2. the injection molding process, the screw can be "inverted "(pressure release) to ensure that the bottom of the billet is well formed, which is particularly important for the" one-step method ", otherwise the bottle is easy to leak the bottom.
Choose the appropriate heating temperature, the hot runner temperature is 2~4 degrees lower than the cylinder temperature. Cooling, injection, holding time even open, mold time and injection, pre-plastic speed to have a good coordination, so that the cycle * short.
Design and manufacturing technology of bottle mould:
1.PET beverage bottle is first preheated on the injected bottle embryo, then the bottle embryo is moved into the mold cavity and cooled into the high pressure air expansion bottle embryo. Generally, the volume of the bottle must be satisfied with the following basic requirements.
The volume of beverage bottle generally refers to the volume of water in the bottle when the difference between the height of the liquid level and the height of the bottle mouth reaches the point of departure. The allowable error range is generally about 1%.
height of the 2. bottle. Because each volume size of the beverage bottle should be packed with the size of the packing box, so the height of the beverage bottle is according to the volume specification can not be changed at will. ) bottle mold exhaust.
When high pressure air is injected into the bottle embryo, the air in the bottle cavity must be discharged immediately to obtain the full bottle sample.
3. generally open the exhaust groove on one of the two cavities. The groove width is 6~8 mm the groove depth is 0.05~0.1. Because the locking force of the bottle blowing machine does not greatly increase the bonding pressure of the two die cavities, the outer milling of the cavity matching surface should be reduced by about 03 mm to reduce the area of the matching surface.
A number of exhaust holes should also be provided at the bottom of the bottle cavity. ) The bottom of the bottle. In order for the bottle to be placed smoothly, the middle part of the bottom of the bottle must be concave upward. In addition, a bad groove must be designed to prevent the middle recess of the bottom of the bottle from cracking when the drink is injected into the bottle.
4. beverage bottle is based on the basic requirements of the PET beverage bottle. The general steps of using the UG to design the beverage bottle are as follows: according to the two-dimensional drawings or bottle samples provided by the user, and other requirements, The bottle sample is preliminarily designed with the Modeling module.
If the band volume of the initial bottle sample is not in accordance with the requirements by using the Analysi analysis tool, the volume is adjusted by modifying the diameter of the bottle or modifying the bottom of the bottle to meet the requirements under the premise of ensuring the same height.
With volume is below the liquid level, the actual volume inside the bottle plus the volume outside the bottle. The volume of the bottle can be calculated by dividing its weight by its specific gravity.
Because the weight of the bottle is fixed, its volume is also fixed. Amplify the bottle model with Scale to compensate for the cooling shrinkage of the bottle.
PET plastic has a shrinkage of 0.7'0.8%, we generally set the magnification factor to 1 0.0075. The bottle solid model is converted into a mold cavity using the UG Boolean operation function. The design of guide column, guide sleeve hole, cooling channel and exhaust groove is made by using the basic characteristics.
5. beverage bottle mold design and processing method when the bottle embryo is injected with high pressure air, the bottle embryo expands rapidly around, and the air in the bottle cavity must be discharged immediately to obtain the full bottle sample.
In order to obtain good exhaust effect, an exhaust groove should be set up on the parting surface, and an exhaust hole should be made in the bottom corner of the bottle which is easy to retain air. Generally, only two cavities are opened on the parting surface of one of them.
The width of the 500 ml beverage bottle is 5 mm and the depth of the tank is 0.05'0.1 mm and three are opened on the sea side. Because the locking force of the bottle blowing machine does not greatly increase the bonding pressure and compactness of the two die cavities, there are 5 mm wide contact surfaces around the cavity. Contact surface outside milling sinking about 0.3 mm.
6. because the bottom of the bottle is five-petal plum-shaped in each corner of the two exhaust holes, a total of 10 exhaust hole aperture of 0.6 mm using EDM high-speed perforation. The bottom of the bottle and the mouth of the bottle must be concave upward in order to keep the bottle steady.
The five-petal plum-shaped bottom also has the function of stopping rotation in automatic canned drinks. In addition, to prevent the bottom from cracking when the drink is injected into the bottle, the middle concave part of the bottom of the bottle is designed with a bad groove.
The bottle mouth part of the 7. mould is made of stainless steel 2 Cr13, which can jam the thread part of the bottle embryo and hold the bottle embryo when blow molding. There are three groups of decorative stripes in the shoulder part of the bottle, and three sea groups with 120 angles between the adjacent two groups.
There are two groups of trims symmetrically falling on the left and right sides of a bottle cavity as shown. The two trims at the edge of the die cavity form an inverted buckle, and the three coordinate NC milling can not be machined completely, so we designed the support.
The die cavity is supported to facilitate the use of electric sparks to process the neat trim. The remaining group falls between the shoulders of another bottle cavity and can be processed directly.
8. molding part of the 500 ml five-petal plum-bottomed beverage bottle is mainly composed of two bottle body cavities and one bottle bottom cavity. For observation convenience, the assembly structure of a die cavity and a bottom plate is omitted.
Discussion on cold air processing of unembroidered steel parts: Pengchuan Mianyang 621000, School of Science, Technology and Manufacturing, Song Hongwen Southwest University of Science and Technology, processed the parts that meet the requirements of the test model.
The experimental success of cold air cutting stainless steel has created conditions for aviation experiment level. Die cavity CAM programming and NC machining this mold parting surface through the beverage bottle axis to divide the bottle cavity into two pieces.
9. cavity rough machining, cutting tool with 20 flat bottom knife JUD working surplus set to 0.5 mm. using CavityMill stratified iron cutting sea layer cutting depth of 3, the type of using FollowPart bad cutting, line spacing 16
Spindle speed know 1500 in. feed adopts spiral lower knife speed) cavity semi-finishing > using FixedContour method to process 3 axis multi-surface projection method. All cavity surfaces are selected by 16 ball knife reciprocating (zig-zag) along the% axis (radial).
The machining surplus is 0.15 mm, the cutting distance is 1 mm. the spindle speed is 5=1800 r/bin, the normal cutting speed is the lmm/fnin, method, and the 8 ball knife is used to cut back and forth along the% axis (zig-zag).
The machining allowance of all cavity surfaces is 0, the line spacing is 0.25 mm. the spindle speed is 5=3800 r/fnin, the cutting speed is 2000 mm/fnin.
