What Is a Machine Screw?

Screw refers to the screw (foreign name: Screw), which is a tool that uses the physics and mathematical principles of the circular rotation and friction of the bevel of the object to gradually tighten the objects and parts. Screw is a common term for fasteners, spoken daily.

Screw is a common fastener and is widely used in machinery, electrical appliances and buildings. The general material is metal or plastic, which is cylindrical, and the grooves with embossing on the surface are called threads.

Due to the different units of measurement, the representation methods of various threads are different. For example, M16-2X60 represents a metric thread. His specific meaning is that the nominal diameter of the screw is 16MM, the pitch is 2MM, and the length is 60MM. Another example: 1 / 4-20X3 / 4 indicates that it is English

The Greek mathematician Alkutas once described the principle of screws, screws, and screws. In the first century AD, the Mediterranean world began to use wood screws, screws, and screws in screw presses, which can be used to press olive oil from olives or to make juice from grapes. Before the fifteenth century, metal screws, screws, and screws were rarely used as fasteners in Europe.

Rybczynski proved that hand-held screwdrivers and screwdrivers already existed in the Middle Ages (as late as 1580 AD), but it was not until the eighteenth century that commercialization of threaded fasteners began to be widely used .

There were many different ways to fasten threaded fasteners before they were widely used. Most of it is related to woodworking and forging, and has nothing to do with machining. The concepts used are dowels and pins, wedges, tenon, dovetails, nails, forged welding and other knotting with leather or fiber. Before the middle of the nineteenth century, shipbuilding was fixed with split pins, pin bolts or rivets. There were also adhesives at that time, but there are not as many types as modern ones.

Machine tools have been used in the eighteenth century to mass produce screws, screws, and screws. Metal screws, screws, and screws have become common fasteners. This technology was developed in the 1760s and 1770s, following two separate processes. Approach, but soon merged: wood screws, screws, screws (metal screws, screws, screws used for wood fixing) are processed by single-use, high-yield machine tools, and low-volume, mold-shop production V thread mechanical screws, screws, screws, you can choose a variety of different pitches.

The first process method mentioned above was first proposed by the brothers Job and William Wyatt of Staffordshire, UK. They applied for a patent in 1760, and they can be called screws at most Earlier versions of the screw and screw machine, which used a lead screw to guide the cutting edge to produce the required pitch. The screw groove was generated by a rotary file, and the spindle was stationary at that time. It was not until 1776 that they built the first woodworking screw, screw, and screw factory and began operations. Their business failed, but the new owners improved their operations. In the 1780s, 16,000 screws, screws, and screws were produced in one day. Only 30 workers were needed. The productivity and capacity of this industrial production are current industrial standards. It was a revolutionary breakthrough.

The production of screws, due to unreasonable production aspects, is likely to lead to screw quality problems. During production, many screw quality problems may be found during delivery. Let's talk about the quality problems often encountered by screws and what causes them. Finally, some solutions are proposed.
1. The head of the screw is deformed, and the head is distorted. The possible reasons are poor installation and improper adjustment of the screw die.
2. The head of the screw is not rounded. The reason is that the improper selection of a die for the screw mold or the full formation of a punch is not sufficient.
3. The screw has burrs or burrs. The reason is that the forming of a punch is bad, which is mainly caused by the gap between the punch and the die hole is too large or the punch is too short.
4. The screw head is cracked, and the screw head has cracks. The reason may be that the quality of the screw wire itself is wrong, so before the screw wire is headed, it must be inspected by the quality department and used with a potion. Especially for stainless steel screw wire, it is necessary to check that it is stainless steel 201 and that is stainless steel 304. It may also be due to the wrong use of a die (such as a die with a hexagonal washer for the pan head) and the failure of the viscosity of the lubricant. For the problem of the screw head, you can read the article written by Manager Zhu above-high strength screw break or head crack detection. In this article, I clearly introduced some problems encountered in the head of the screw and how to detect the problem of the screw head ^[4] .
Of course, the common quality reasons for screws are not limited to the above, this is only part of it. There are other quality issues, and then Manager Zhu is talking about it. The above screw quality reasons are for reference.
If you encounter these problems, you can try according to the proposed solutions.