Thread Manufacturing Process

Threading parts is a basic metalworking procedure. Machining thread should never be taken for granted by any manufacturer. Connectors and fittings are now widely available on the global market. As a result, finding the correct threads for your applications becomes increasingly difficult.

The thread cutting methods appear to have a number of flaws as well. These methods, however, are still among the most efficient for creating screw threads. It is critical to investigate the various threading methods available in order to maximise your profit margins. Continue reading to learn critical details regarding threading machining.

In manufacturing, what is a machining thread?

A continuous helical ridge is referred to as a thread. On different surfaces of a cylinder or cone, the helical ridge has a consistent section. It can occur on the surface of the nut (internal) or the screw/bolt (external).

The basic role of a thread is to act as a link between two mechanisms.

As a result, the motion can assist in obtaining mechanical advantages. The following definitions will aid in your understanding of machining threads:

Crest: This is the thread’s surface that connects the flanks. The crest is the place where the thread projects the most from the cone or cylinder. That is to say, it is at the very top of the threads.

Flank: The flank of a thread connects the crest to the root. The intersection of a flank surface with an axial plane is a straight line in theory.

Root: The thread surface that connects the sides of adjacent thread forms is known as the root. The thread projects from the area immediately adjacent to the cone or cylinder. That is to say, that is the end of the threads.

Helix Angle: The helix angle is the angle that the helix makes in reference to the thread axis when you have a straight thread. The helix angle of a taper thread, on the other hand, is determined by the conical spiral area of the thread.

Types of Machining Threads

There are several different criteria for classifying threads, The internal and external threads will be discussed in this section.

Internal Thread

A screw thread on a concave surface is known as an internal (female) machining thread. A single-lip threading tool is used to create these threads. The classic threading tap is used for some internal threads. A tap is a metal tool that is used to cut internal threads on CNC machining components.

To place a screw into your workpiece, you’ll need an internal thread. On internal threads, thread cutting can be done using hand taps or machine taps.

To begin, calculate the diameter of the hole you require. Then there’s the matter of knowing which tap to use for cutting. The nominal diameters of internal machining taps are used to classify them.

The diameter for tapping can be calculated using the formula below:

Tap diameter — Thread pitch = core hole diameter.

A punch is used to centre the thread during the cutting process. The twist drill can then be used to drill a core hole. The 900 countersink assists in the creation of a chamfer in the core hole. By inserting the tap into the tap wrench and turning it into the core hole, you can now cut the thread.

External Thread

A screw thread is another name for an external thread. Screws, plug gage, bolts, and studs are examples of external threads. An external thread can be used to expand the length of pieces that qualify for turning.

Threading on a lathe is highly effective for external threads. You can also use a round die to cut by hand. In most cases, the die is stored in a set die stock. Round dies are used by manufacturers as an internal thread’s counterpart.

Hexagonal square dies are also available. Interlocks are the ideal use for these types of dies. They assist in the repair of cases as well as the transportation of dies to inaccessible areas.

The edges of the round rod must first be filed. Then, at 450, chamfer the rod. The thread depth should be somewhat larger than the chamfer. The round die can then be clamped and fixed. To cut the thread, the rod requires a large amount of pressure. Cutting sprays aid to increase the part’s surface quality while also extending its life.

What Is the Best Way to Cut a Machining Thread?

Thread cutting aids in the creation of screwed connections on parts. Internal threads are required for connections made with complete screws. Many of these connections also require corresponding external threads to function as a counterpart.

Understanding how to cut threads is an essential skill for single-piece manufacturing. It is also required for repair work. This is due to the fact that machines will not always be useful for economic and technical reasons.

The top methods for cutting machining threads are as follows:

Milling:

This method makes use of a revolving milling cutter. The shape of the cutter conforms to the desired thread shape. Manufacturers use either a single or multiple cutters. Every cutting edge in a single cutter is present in a single plane. The multiple cutters, on the other hand, have several rows of annular cutting teeth.

Threading on a Lathe

Thread cutting on a lathe is another important threading process. This method creates a helical ridge on a workpiece.

Die-Cutting

The die-cutting method is the most commonly used method for cutting external threads. Die-cutting produces parts relatively quickly. As a result, they are cost-effective methods of thread cutting. This method has a medium level of precision and quality. However, it is perfectly acceptable for the vast majority of mass-produced parts.

Thread Machining Design Top tips

Internal threads should have a countersink at the end.

If no specifications are given, lower-height threads are preferred over higher-height threads.

It is more cost effective to use standard thread sizes and forms.

The thread’s starting end should have a flat surface that is parallel to the thread’s central axis.

To withstand the pressure of forming or cutting, the tubular parts should have increased wall thickness.

Parts’ external thread ends should be chamfered.

Conclusion

High-quality parts necessitate a thorough understanding of manufacturing processes. Machining thread cutting is an important aspect of manufacturing processes. Despite the fact that it appears to be a little complicated, it is not advised to abandon the idea.