AYA FASTENERS Guide | Conventional Self-Tapping Screw Production Process

When it comes to the creation of any project there are usually several completely separate parts that will need to be addressed. From designing to manufacturing to assembling there are several aspects of the project that can fundamentally change how easily each part can be completed. One of the most important changes that you can make if you want to reduce the assembly process of your project is to use self-tapping screws. These types of screws can help you completely get rid of drilling, but they could end up adding extra steps to your production process.

What are self-tapping screws?
Self-tapping screws have a head and part of the body that looks completely similar to a conventional screw. However, at the bottom of the body part, they include a drill bid. This was used for drilling through material with the screw, thus eliminating the need for a separate drill hole to be created. In order for the drill bit at the end of the self-tapping screws to be created a dedicated electric tool is used.

What is the structure of a self-tapping screw?
A self-tapping screw is normally created from three different parts. The head, pole, and the end of the rod. The head can take a number of shapes in self-tapping screws, however much like with common screws, rounded heads of different types tend to be the most common. Hexagon, flat undercut, flat trip, square, and truss head types are all available in self-tapping screws.
The threads in self-tapping screws can also come in a variety of forms, including self-tapping threads, drywall nail threads, machine threads, and others. Another aspect of the threads that you need to be aware of is that they can be divided into five categories: single-guide, double-headed, high-teeth double thread, low-teeth double thread, and multi-guide.
Finally, the end forms can also come into different forms, with the screws either having a peace end or a cone end. However, depending on the purpose of your screw there are also a number of other manufacturing options for different types of ends that will help fit better with your material.

What are the types of self-tapping screws?
There are several different types of self-tapping screws, however, the ones you will most commonly find are:
1. Ordinary Self-tapping screws: these are also referred to as wide tooth thread and their surface is usually electroplated.
2. Cut self-tapping screw: Self-tapping screw scrapping end is the standard used by China. Usually, these will either have a thread that is a self-tapping thread or a machine thread. The cross groove will tend to be “H” type.
3. Self-squeezed Self-tapping screw: these are also referred to as self-tapping lock screws and usually they will have machine threads. The screw cross section will most likely be triangles, which is why these can also be called triangular thread screws.
4. Metal drive screw: these can be long and will usually have a special thread that is in a certain spiral angle. These do not fit the standards in a number of countries.
5. Drilling self-tapping screw: these screws have a machine thread and it is not usually recommended for them to use ordinary hexagonal heads or slots.

The different types of self-tapping screws have changed based on the changes in production and technology over the years. The new structures, materials, and thread forms have all played an important role in the changes in technology.

What are the characteristics of a self-tapping screw?
The most distinctive characteristic of any self-tapping screw is the fact that it has a drill head at the bottom. This allows for drilling, tapping, wire, and locking to happen in one step. They will usually also have some kind of finish that allows for strong corrosion resistance, this is because these types of screws are often placed outdoors.

What are self-tapping screws made of?
A self-tapping screw is usually created through either stainless steel or carbon steel. However, many different options for the surface treatment of these screws could fundamentally alter their properties.

What are the uses of self-taping screws?
Self-tapping screws are particularly common when it comes to connecting and fixing thin sheet parts, including the connection between several color steel plates, or color steel plates and wall beams or bars. They are also particularly useful in cases of wooden material, as they can get the exact screw hole completed without the need for an additional drill.

How are self-tapping screws described?
When it comes to the description of self-tapping screws there are usually three parameters to be considered. These are the number of screws per inch length, the screw diameter level, and the screw length.
When it comes to the number of screws per inch the usual numbers are 14, 16, and 24, while screw diameter comes in two types level 10 and level 12. The screw diameter corresponds to 4.87mm and 5.43mm.

What is the production process for self-tapping screws?
The production process for self-tapping screws includes several steps and production equipment that are necessary for the creation of the screws. The production process for screws usually follows the steps outlined below:
1. Drawing/ Wire drawing
Wire drawing as drawing is most commonly referred to, is the process in which the wire is pumped to the cold-heading machine. Prior to wire drawing, there is usually pickling which is used for the removal of the oxide film that is on the wire’s surface. The wire has a phosphate film created at the surface which helps to reduce the wire’s roughness and removes all of the scratches on the mold that might have been a result of the debris.
Following this process, the wire coil is pickled and then cold drawn through the use of a wire drawing machine.

2. Forming
Once the drawing process is complete the next step is the formation of the head. Normally for the head formation, the process of one die and two punches is used. The shape of the head will also be chosen during this process.
The formation process occurs in the following way:
Blocking: first, the wire that is stuck in the cutting die will need to be cut to the necessary size.
First Punch: The product head is formed through one punch fixing the mold. In cases where the product is a straight groove, then the one punch turns into a concave or elliptical groove. In cases of a cross groove product then the other punch is a concave square groove.
Second Punch: Following the first punch, the second punch is used for the formation of the end of the product. The back punch will push out the blank.

3. Thread rolling
In the case of self-tapping screws, a nail embryo is formed into a thread. This requires two tooth plates, where one is fixed while the other is rolled. This process also includes the deformation of the product through kneading it to form the necessary thread.

4. Heat treatment
In screws that have hardness requirements, heat treatment is required. Self-tapping screws will often have requirements in terms of surface hardness and core hardness that they need to meet.

5. Surface Treatment
Much like in normal screws, the surface treatment is a process by which the piece is going to be covered by a layer of some other type of material through a surface treatment method. Usually, surface treatment is either used for bettering the appearance of a product or to give it further qualities, such as anti-corrosion, which can be useful based on the location you are in.
The most common surface treatment methods used include electroplating, mechanical plating, and hot-dip galvanizing.

Are the five processes enough for the production of self-tapping screws?
Once the five processes are completed you will have in your hand completely formed self-tapping screws. However, there is always one additional step that should be taken following the production of any screws and that is known as quality control. During the selection and checking of the products, any defective products you might have should be taken out of the batch. Once the final selection has been made the products will be ready to be packaged and labeled.

Conclusion:
Self-tapping screws can make the assembly process of any of your projects far quicker and easier. However, that usually means that you will need to take some extra care in finding good-quality screws for your projects. The production of these self-tapping screws can be fairly easy to understand once you gather all the information about each of the steps. More importantly, if quality control is performed accurately you will be able to have great quality screws that will help simplify the assembly of all of your projects.

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