Plastic transformer skeleton product design and mold design and manufacturing:The process generally designs the detailed structure of the skeleton according to the requirements of the customer (transformer manufacturer). At present, the skeleton is designed for the customer, and the skeleton manufacturer directly opens the mold according to the designed skeleton. However, there are a few cases where the customer provides samples or a simple design drawing, and the skeleton manufacturer cooperates with the previous design work. When designing the skeleton, pay attention to the following details to reduce some of the defects that often occur during production.

1 In the early stages of the skeleton design, the designer needs to have a clear understanding of the use of the skeleton at the customer. Including the customer's transformer finished product requirements, such as the external dimensions; transformer production process and production conditions of each process, such as soldering temperature, soldering time, baking temperature, winding method, etc.; magnetic core model, size, etc. . In short, the precautions of the skeleton when using it on the client must be clearly understood in order to better carry out the next design work.

2 In the design of the skeleton structure, according to the drawings or samples provided by the customer, plus their own design experience, try to design the model in 3D, avoid the defects of 2D drawing and modification, and then gradually modify it to finalize the case. If the customer design is unreasonable, you should take the initiative to re-confirm the skeleton structure with the customer's technical staff. When designing the skeleton, pay attention to the following aspects:A Raw materials must conform to the customer's process and requirements, and must be designed according to the characteristics of the material. Generally, the yellow wall is used to confirm the wall thickness of the skeleton. At the same time, the temperature indicated by the yellow card is compared with the baking and soldering temperature of the customer's process to meet the customer's process conditions. For example, GE's N300X raw material has an RTI Elec temperature of 105 degrees and a customer baking temperature of 130 degrees. Obviously, this raw material does not meet the customer's process conditions.B Metal pins can smoothly pass or flatten the PCB board of the client, and generally use iron (steel) stitches. When there is a special requirement for the customer to have better conductivity, it is necessary to consider a material with good conductivity such as copper.C At present, environmental protection requirements such as RoHS, halogen-free, and SVHC are becoming more and more urgent. These materials must meet these requirements at the same time.D must meet the transformer model requirements, and the external dimensions should be smaller than the finished transformer size.The E core hole needs to match the size of the core center column, which is generally larger than the upper limit of the core; the fixed core blade is generally smaller than the core inner diameter lower limit tolerance. The purpose of this design is to modify the mold for subsequent wear. The frame type skeleton is suitable for the tightness in the automatic winding operation of the customer (the loosening of the frame during the winding process will cause the skeleton to fall off, and the operator is difficult to insert or pull out), the core hole and the winding fixture The tolerance of the fit should be controlled at around 0.05.F The line groove is the path of the copper wire. At the same time, in order to avoid abnormalities such as breakage, pin cracking, sand inclusion, etc., the width of the wire groove needs to be considered together: the diameter of the copper wire and the edge of the pinhole Wall thickness and burrs handle the size of the sand. Under normal circumstances, the wire trough is suitable for large, so as to avoid sanding, and it is convenient for customers to pass the copper wire. However, when the wire trough is enlarged, the remaining pinhole edge thickness will be small, and the pin is prone to occur during production. Cracked feet.G pinhole should not be too deep, the wall thickness of the bottom of the pinhole should be guaranteed to be more than 0.5mm, avoiding the cracking or piercing of the pin.H needs to do the R angle transition, in addition to increasing the strength to prevent damage, it can also improve some problems in production. In particular, the edge of the wire groove can prevent the insulating enamel coating on the outer layer of the copper wire from being scratched; the edge of the core hole can facilitate the insertion of the magnetic core; the strength of the blade can be increased around the winding pipe.I Need to design the pin anti-reverse structure to best effect the bump, so that the groove and the bump can be added in the direction corresponding to the runway to avoid the misalignment caused by the product.J The frame with a high retaining wall or a large blade has to be designed with a draft angle to facilitate demolding during production.When the K-frame has a matching cover, pay attention to the size of the joint with the cover.The blade in the middle of the L-frame bobbin winder should be designed with corresponding hooks to prevent the copper wire from being in place when the wire is wound; the blade should also be designed with a notch so that the winding needle can pass smoothly.It is better to design the recessed notch at the M inlet, depending on the size of the skeleton. Generally, the notch is 0.5-1.0 mm deep. This can avoid the influence of the residual material at the time of material selection on the external dimensions of the product. If it is not possible to design a notch, increase the jig of the grinding feed to meet the size requirements.N Plastic frame with thick wall thickness should be designed with recessed notch in plastics, try to ensure uniform wall thickness and avoid serious shrinkage.

3 mold design and manufacturing.

A customer is only a sample developed by the sample. The mold can be designed with one or two holes. It can be used for proofing production. Customers who require special production in small batches can heat treat the mold or choose better steel.B Mass-produced products can be designed in a straight line for the processing of mold cavities, runners, and exhaust slots.C The part where the front mold, the rear mold and the slider cooperate with each other should be designed with the inclination to avoid mold damage caused by direct collision.Deeper parts of the D-cavity (such as the bottom bump or retaining wall) should be designed with draft angle and venting holes to make the exhaust smooth during molding and reduce the occurrence of less material.E Mold insert specifications are as versatile as possible and easy to replace and clean for timely replacement and repair.

4 sample detection and recognition phase. When the project or business delivers samples, the products must be rigorously tested and checked:

A Product size, especially the important parts and wall thickness required by customers as the focus of control.B strength test, the general skeleton can reach 3Kgf, the strength is relatively small when the structure is thin or the product is small.C Withstand voltage test, through high voltage test (such as 3.5KV, 2mA, 60S withstand voltage conditions), in the design stage can avoid the pressure tolerance caused by the material selection, wall thickness is not reasonable.D Solder test, test the tin on the pins, and the deformation and blistering of the body after an instant (1-3S) high temperature.E Product flatness, test the bottom bump or plane in contact with the PCB board, whether there is warpage deformation, the industry generally uses 0.1mm max as the standard for control, the larger the skeleton, the relaxation of the flatness size. At present, the stitching of the frame-type skeleton is the most strict, because the stitch flatness is the control point directly related to the PCB flat post.