Galvanized sheet: It is a zinc layer coated on the surface of cold-rolled sheet, commonly known as galvanized sheet. Galvanized sheets include SECC, SGCC, etc., and galvanized sheets are rust-resistant and corrosion-resistant. The price is relatively high. The common plate thickness is 0.4~3.2mm. Its features are excellent paintability, good fingerprint resistance, good corrosion resistance and maintains the processability of cold-rolled sheets. Generally, the thickness of the case and the lower cover is 0.80mm SGCC material. Medium hardness, slightly harder than aluminum, slightly softer than stainless steel. The SGCC material is relatively hard, and its tensile properties are not very good. If this material is used for stretching, the die and punch must be polished very brightly, otherwise it is easy to crack and crack.
Stainless steel: It can be used to produce shrapnel and appearance parts of various sizes. For example, the shrapnel inserted into various interfaces at the back of the desktop computer case is made of stainless steel and then produced through stamping dies. The material of stainless steel is relatively hard. Sometimes the gasket cannot be found in the mold maintenance, and the stainless steel material can be used for emergency. The punch and knife edge of the stainless steel mold need frequent maintenance to ensure the smooth production of the mold. Otherwise, mold repairs are often required. Ha ha.
Generally, the gasket needs to be placed on the part with a spot welder, otherwise it will be more troublesome if it falls off when the mold is removed next time. Some factories do not allow the use of gaskets. At this time, you can use welding to burn them up, and then use a grinder to grind them out to the required size.
Commonly used stainless steel materials are SUS301, SUS304 and so on. SUS200 series (including 201, 202, etc.)
SUS300 series (including 301, 304, 310S, 321, 316L, etc.) and
SUS400 series (including 409, 410, 420J1, 420J2, 430, 436L, 444, etc.)
Tinplate: Tinplate? Are you a little dizzy? At that time, I heard the master in the factory say that it was tinplate, and I also mistakenly thought it was “mokou iron”. wrong. In fact, I can’t tell the difference, anyway, the pronunciation is ‘mokoutie’. Simply think that it is mottled iron! The ductility of mottled iron is relatively good, the hardness is not high, and it is relatively soft. Generally, mottled iron material is suitable for stretching more complicated curved surfaces, and it is not easy to crack. Such as the upper cover. Some small shrapnel etc.
Tinplate, where Sn is the coating, tinplate is also called tin-plated iron. Tinplate is a common name for electroplated tin sheet steel. Tin mainly plays a role in preventing corrosion and rust. It combines the strength and formability of steel with the corrosion resistance, solderability and beautiful appearance of tin in one material, which has the characteristics of corrosion resistance, non-toxicity, high strength and good ductility.
7.9. What is pitch positioning?
What is pitch? What does pitch positioning mean?
Pitch, as the name suggests, refers to restraint, and “pitch” refers to control distance. Then the pitch positioning means positioning by controlling the distance. Control the feeding distance to avoid over-feeding, mis-feeding, damaging the mold, or producing defective products.
In stamping dies, pitch positioning is generally used in continuous dies.
People who know it will say: “Nonsense, how can engineering molds be used for pitch positioning?” 。
Why only continuous molds use pitch positioning, but engineering molds generally do not use pitch positioning?
That’s because the general engineering molds are made of blanks, and the size, length and width of the blanks are almost the same, just put them directly into the engineering molds and punch them, otherwise they wouldn’t be called “engineering molds”; of course, engineering molds also have For automatic feeding, the feeder is generally set up, and the punch will be punched, and the feeder will automatically send the material.
The continuous mold generally has a special automatic feeding machine, otherwise how to make it? Manual feeding Because sometimes the feeding is not accurate, the product scrap rate is too high, and the automatic feeding machine can avoid this risk. Moreover, only ordinary small factories use manual feeding, and slightly larger factories are arranged to have automatic feeding machines. Manually only need to place the material on the automatic feeder according to the requirements, and then set it up.
However, the automatic feeder may not be so accurate, and sometimes there will be a small error. At this time, the pitch positioning plays a very important role. Some people say “pitch positioning: the distance between two positioning pins.” Think about it, right? In fact, this statement is not wrong, in theory it is so. But what is the distance between the two alignment pins? How is it calculated? Haha, this question is too profound, you can ask a master who specializes in hardware mold design.
Let me give a picture below to briefly talk about what pitch positioning is.
Among them, the blue area is called the material belt, and then there are two red circles, which are the positions of the knife punch. I will not talk about the knife punch here. I will write a blog next time when I have a chance. Let’s talk. This time the main discussion is pitch positioning, okay, let’s continue. There is a pitch positioning block here, let’s call it pitch positioning for short, because we often say that in mold making, such as “Where did you put the pitch positioning?” “Do a pitch positioning Let’s go.” The pitch positioning here refers to the block of pitch positioning.
Pitch positioning is usually installed on the lower mold, where the strip first comes in, and the strip first enters from the beginning of the continuous mold, and then punches two holes (positioning holes), then passes through the tool setting place, and passes through the tool setting process. place, cut the edge here, cut off a part of the material tape, and then block the material tape through pitch positioning to prevent misfeeding.
Notice the two red circles? what is that? Why circle it? think about it.
In the first red circle, there is a small gap there, why should there be a gap in this place? without cutting at a 90° right angle? think about it.
Because what’s behind it? The back is pitch positioning. Pitch positioning is generally made at right angles here. Think about it, what if the front cutting edge is also a right angle here?
The cutting edge is right angle, so the punch must also be made at right angle, because the right angle is a sharp angle, and the material of the general punch is very brittle, although the hardness is very high (the higher the hardness, the more brittle, I don’t know if I say this Correct, don’t mislead you! .
It is very brittle, and it is easy to break. After many times of production, the small sharp corner on the front may disappear. Is it still cut at 90 degrees at this time? Even if it is 90 degrees, there will be a lot of burrs, and it will be uncertain when it comes to pitch positioning, and the printed products will have errors . Do you know now? Why is there a small gap there?