What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
GBT 3098.19-2004 blind rivets in my country are divided into: GB/T12615 closed oblate head blind rivets; GB/T12616 closed countersunk head blind rivets; GB/T 12617 open type countersunk head blind rivets; T 12618 Open-type oblate head blind rivets; the international standard is DIN7337; there are 1990 versions and 2004. The 2006 version is mainly the 2006 version.
The produced screws, due to unreasonable production aspects, are likely to cause quality problems in the screws. During production, many screw quality problems may be found upon delivery. Let's talk about the quality problems often encountered by screws and the reasons for the quality problems, and finally put forward some solutions. 1. The head of the screw is deformed and the head is crooked. The possible reasons are the poor installation of the first punch of the screw die and the improper adjustment of the machine. 2. The head of the screw is not round. The reason is that the selection of the first punch of the screw mold is improper or the first punch is not full enough. 3. The screw has burrs or burrs. The reason is the poor forming of one punch, mainly caused by too large gap between punch and die hole or too short punch. 4. The screw head is cracked and the screw head is cracked. The reason may be that there is a problem with the quality of the screw wire itself, so before the screw wire is headed, the quality department must check it and use the potion. Especially the stainless steel screw wire, it is necessary to check that it is stainless steel 201 and that is stainless steel 304. It is also possible that a die is used incorrectly (such as a die with a hexagonal washer head for a pan head), and the viscosity of the lubricating oil fails. For the problem of the screw head, you can read the article written by Manager Zhu above - high-strength screw fracture or head crack detection. In this article, some problems encountered by the screw head and how to detect the screw head problem are clearly introduced [4]. The common quality reasons for screws are of course more than the above, this is only part of it. There are other quality issues, then Manager Zhu will talk about it. The above screw quality reasons are for reference. If you encounter these problems, you can try the solutions proposed.
The history of screws was broadcast in 1986. Our country formulated a new standard for standard parts, which is commonly known as the new standard in the business. The most used ones are GB5780, GB5781, GB5782, GB5783, GB5784. GB5780 is a hexagonal head thick shank half-thread screw, its accuracy grade is C-grade product, which can be replaced by GB5782 (GB5782 is a hexagonal head thick shank full-thread screw, and its accuracy grade is grade A and B.) GB5781 is a hexagonal head full-thread screw. Threaded screw, the accuracy grade is C grade product. It can be replaced by GB5783 (GB5783 is a hexagonal head full-tooth screw, and its accuracy grades are A and B). GB5784 is a hexagon screw with thin rod and half teeth.
Slotted Round Head Wood Screws GB 99-86 Slotted Countersunk Head Wood Screws GB 100-86 Slotted Half Countersunk Head Wood Screws GB 101-86 Hexagon Head Wood Screws GB 102-86 Cross Recessed Round Head Wood Screws GB 950-86 Cross Slotted countersunk head wood screws GB 951-86 Cross recessed countersunk head wood screws GB 952-86
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