C14 breath detector is a modern instrument for detecting Helicobacter pylori. Breath sampling has high detection sensitivity, high detection rate and coincidence rate, and no pain for patients. It is the most popular method for detecting Helicobacter pylori. Bottom case of C14 detector is shown in Figure 1. Maximum external dimension of product is 417.03 mm * 348.70 mm * 149.72 mm, average thickness of plastic part is 3.12 mm, plastic part material is ABS, shrinkage rate is 1.005, and weight of plastic part is 986.83 grams. Technical requirements for plastic parts are that there shall be no defects such as peaks, underfilling, flow lines, pores, warpage deformation, silver lines, cold materials, and spray lines.

 

Figure 1 C14 detector bottom case product map
It can be seen from Fig. 1 that plastic part structure is a closed rectangular shell with ups and downs in height direction. There is an inclined hole at sinking part of side of high end of tail. It is necessary to design fixed mold inclined slider core pulling, inner glue position is recessed, and lifter needs to be designed. There are 4 pits on the bottom surface of high end face shape, forming an upside-down buckle, and it is necessary to design core pulling of movable die slider. Low profile of end face has 3 small holes to form mold inverted buckle, and it is necessary to design core pulling of movable mold slider. There is a side window on the side for assembling transparent parts. There is a whole circle of through grooves on the edge of mouth of plastic part, and a bone position is connected in the middle. These grooves have a large tightening force on movable mold core, and care should be taken when plastic parts are ejected. There is a bone position in the middle of back mold with same depth as plastic part, and inserts need to be designed here to facilitate processing.

 

Size of plastic part is large, mold design cavity ranking is 1 cavity, sliders at both ends are located on sky side and ground side of mold respectively. Main consideration is that robot can achieve a balance when it is ejected. Glue feeding method is that sprue gate directly feeds glue on the top surface of plastic part, and sprue condensate is cut off immediately after injection molding.
Injection molding competition is becoming increasingly fierce, molding quality and efficiency are related to survival of enterprises. To improve production efficiency, it is necessary to race against time and realize automated production. Degree of automation of equipment in plastic products production enterprises has also become one of important indicators to measure comprehensive strength of enterprises. High-quality customers also hope to cooperate with injection molding manufacturers with robots. Use of robots can largely overcome inertia of labor, can accurately calculate daily output and delivery time. Use of manipulators can deal with many challenges such as high labor turnover, shortened lead times, and safety issues. Manipulator takes out product and places it on conveyor belt or receiving table. Only one person is required to take care of it or one person can watch two or more injection molding machines at the same time, which can save labor. Making automatic assembly lines can save factory space and make the whole factory planning smaller, more compact and exquisite.
Molding quality is related to performance of injection machine itself, mold process and surrounding environment, molding efficiency is related to mold accuracy, molding process, and production quantity; due to different molding products, automation application is also very complicated. Manipulator can overcome disadvantages of low labor efficiency and ensure molding product process. Main uses of manipulator are as follows:
1. Manipulator takes out product in mold, replacing original semi-automatic production to full-automatic production;
2. Manipulator takes product out of mold, embeds product in mold (labeling, embedding metal, secondary molding, etc.);
3. After robot is taken out, it will be automatically packaged and automatically put into storage;
4. Automatic feeding system for molding raw materials, waste recycling system;
5. Whole plant production control system, etc.
Use of manipulators can make cycle more stable and more efficient. Machine production cycle of 20S is 20S, which will never change, which is convenient for production management. Due to stability of production cycle, output and profits are increased.
Details make a difference. The slightest thought will bring bad to mold. This set of molds uses a manipulator to grab sprue condensate to realize pick-up. If you do not pay attention to positioning in initial stage of mold design, high and low ends of plastic parts are in horizontal position of mold, that is, operating side and non-operating side, plastic parts will deflect and fall when manipulator picks up parts, which is easy to cause manipulator to make mistakes, which needs to be carefully considered in mold design.

 

Due to large size of mold core, it is difficult to grind and match frame when front and rear mold cores are lowered. Positioning method of mold core is way of pressing block. Mold base is GCH7075 A220 B180 C170. Purpose of selecting simplified fine nozzle is to facilitate design of front mold core pulling at the inclined hole. Four corners of mold base are respectively designed with vertical straight body locks 16, which is convenient for precise mold clamping. Balance blocks are designed on both sides of edge of mold base without sliders to increase pressure-bearing area to bear clamping force of mold.
It should be noted that small slider 25 has an inclination of 6.3゜ in movement direction, angle between top surface of small slider 25 and parting surface in movement direction is an inclination of 6.3゜, which is determined by glue position of plastic part. When this angle is smaller than inclination angle of inclined guide post, it will not affect movement of slider. Detailed calculation readers can use trigonometric functions to calculate.
Edge of plastic part has a large force on back mold, so a straight top is designed on the edge of plastic part to eject. Deep glue position in the middle is also designed with straight top ejection. Rest of parts are designed with cylinder and ejector pin.
Inner glue position of inclined hole at the tail of high end of plastic part is recessed, and a drop-type lifter 41 is designed, see mold design diagram 2.

 

 

 

 

 

Figure 2 C14 detector bottom shell mold diagram

 

Figure 3 3D drawing of mold