CNC Tapping: Process, Benefits and Applications

You would know about a CNC machine and how many operations can be performed using it, so tapping is one of them. It is used to make internal threads within the holes in parts, that’s why it is used extensively in manufacturing industries. This article provides comprehensive information related to every aspect of tapping, its types, uses etc.

What is Tapping in Machining

The tapping process is one of the functions of a CNC machine. It is performed in CNC to make internal threads within the holes of the parts. These threads are required for good fitting of bolts in the nuts etc. Due to the automation feature of the CNC machine, it is performed with great accuracy and efficiency.

What is a Tapping Machine used for

A tapping machine is installed within the CNC machine. A tap is used for making threads within the pre-drilled holes of parts. Tapping machines are commonly used in automotive industries because they efficiently tap the holes in automotive parts such as chassis housing, engine blocks etc. Tapping holes are important because it is necessary to develop the full strength of connecting screws or bolts.

The Best Aluminum CNC Tapping Machine Products

The main things for the best machining of Al are optimum spindle speed, torque, chip management etc. For the best Al Products, you should use the Brother Speedio series (R450X2, S700X2) because of its high-speed tapping and fine accuracy. You can use the Makino F-series because of its high-speed operations. There are many others but these two are the best.

Advantages and Disadvantages of CNC Tapping

CNC Tapping is an automatic and easy machine that’s why it is easy to work with it. As we discussed earlier it is used to make internal threads. Now let’s figure out the detailed advantages and disadvantages in this section.

Advantages

1. Cost-Effectiveness

Since it is an automatic machine that’s why only one skilled operator is enough to operate. Once the feed rate is set, then that automatic tapping machine operates by itself. Since less labor is required hence the low cost. That’s why it is a cost-effective technology to create threads within the components.

2. Productivity

CNC tapping works automatically once the feed rate is programmed in the machine, it works quickly. Its threading speed is faster than the manual machines. Its fast speed of threading results in increased productivity.

3. Consistent Quality

The chances of error during the working are very low because it keeps on working automatically until a third party stops it. A CNC tapping machine is used where tight hole diameter tolerance and high-quality threads are required.

4. Low Scrap and Rework

Since the CNC tapping machine works efficiently that is why it produces very low scrap as compared to manual tapping machines. Its consistent quality results in approximately no errors which is why low rework is required.

5. Repeatability

Once the threading designs are programmed in CNC tapping, it can repeat that threading design on many components.

6. Safety

It is safe to work with automatic tapping machines as compared to manual tapping machines. Because after programming, this machine does not require any worker, which reduces the risks of human injuries during the working.

Disadvantages

Every machine contains some sort of disadvantage as the CNC tapping machine does. Its main disadvantages are given below.

• CNC tapping machines are very expensive means require a huge amount of investment for a single machine.
• To run this machine, complex programming is used which takes enough time.
• To move from one design to another during the workflow is not possible in this machine like changeover requires large amounts of time.
• Since the tap remains in contact with the workpiece that’s why the risk of tap breakage is always present. The second reason is the speed of the spindle is very important.

How Does the CNC Tapping Process Work?

 The principle for CNC tapping machine working is the pre-programming of the feed rate and design. The tapping tool moves to create threads on the surface with the fed speed. The tapping process starts with drilled holes, so drilling is needed to use the tapping process.

Step-by-step Working

• There are a total of two steps for starting the work and the first is to select an accurate tap. These taps are formed using different tapping dies of required sizes and shapes. The tap drills are selected according to the design and size of the threads, screw size, material and the diameter of holes.
• Once the selected tap drill is set in the machine, the operator should program the design and feed rate in the automatic tapping machine and make sure the tapping tool is set or fits in the hole depth accurately.

CNC Mill Tapping: A Versatile Solution for Milling and Tapping

Now, you know that tapping is a process used to make internal threads within the holes of parts like nuts, etc. The other process which is expressed in this heading is the milling process. A milling process is used to make complex shapes of parts by cutting the excessive material. The name “CNC Mill Tapping” provides a hint that we can operate both processes by using this machine, which is why it’s a versatile solution for milling and tapping.

What is Rigid Tapping and How Does it Work?

It is a type of tapping process which uses the synchronization of spindle rotation speed and feed rate to match a thread pitch. It allows for making consistent threads and controls for blind holes.

Rigid tapping is a precise threading method used in CNC machining, where the machine keeps the spindle and tap in perfect sync. As the tap rotates, it moves downward into the material at a controlled speed. Because both the spindle and the tap turn together, there’s no chance of slipping or misalignment, which results in clean and accurate threads.

This is different from "floating tapping," where the tapping head has some flexibility to adjust for misalignments. In rigid tapping, the connection between the spindle and the tap is fixed, leading to more accurate and consistent threads.

Rigid tapping is particularly useful for high-volume production and applications that require precise threads. If you're thinking of using rigid tapping in your CNC work, make sure your machines can handle it and that you're using the right taps for the materials you're machining.

Types of Taps in CNC Tapping

There are many taps according to the material, diameter of the hole etc. used in the CNC tapping machine, but the most common are discussed here.

• Spiral Point Taps

Such taps have straight flutes for the distribution of coolant during work. While using these taps, chips are removed with the help of inclined angular deep cuts on the front end of the tap at the cutting chamfer. If the parts contain through holes, use spiral point taps for tapping.

• Spiral Flute Taps

In the following image, we can see that spiral flute taps have flat ends. It removes materials more quickly than any other tap because there are more cutting edges. To use these taps, there is one requirement which is pre-tapping. These taps are used for blind holes and hard materials where the chip buildup is the problem.

• Form or Roll Taps

As the name suggests, these taps roll the removed material instead of making chips. They are fluteless taps because of no need to evacuate the chips from the surface.

CNC Tapping Tools and Accessories

CNC tapping tools include taps, tap holders, coolant taps etc. Every tool has different functions. For instance, coolant taps are used to provide passages for coolant to control heat during the cutting tapping, tap holders hold the taps etc.

Accessories include the speed of taps, depth stops, torque limiters etc.

CNC Tapping Head

The tapping head controls the taps in working. It is like the liver of a crane. As you push it down, the tap moves down and starts working, as you pull it up tap reverses to its original position means working stops for some time.

CNC Tapping Tool Selection and Setup

Taps are selected based on the material of the workpiece, hole diameter, screw size and thread standards. The setup requires the tap holder, feed rate and coolant to control the heat during cutting tapping.

Types of CNC Tapping Processes

There are several CNC tapping processes which are used according to the requirements. The most common methods are addressed below.

Through Hole Tapping

This process is used for those parts which contain holes of depths of the complete thickness of the workpiece. Spiral point and flute taps are used commonly in this process. It is easy to remove the material because the chips evacuate through the bottom of the holes.

Blind Hole Tapping

Flute taps are used for this tapping process. Since the depth of the holes does not pass through the complete thickness of the workpiece, then it becomes difficult to remove the material due to threads from the holes. These chips are removed manually from the holes.

Floating Tapping and Its Benefits

 In the float tapping process, as the name suggests, a floating holder is used to hold the tap in such a way that it slightly moves, or you can say floats over the axis to manage the misalignments between the workpiece and spindle of the machine. The risk of tap breakage is less because of no contact between the tap and the workpiece.

Synchronous or Self-Reversing Tapping

This process is used to make threads at a faster rate i.e. fast production. The tap automatically reverses to its original position once the cycle is completed so, we do not need to hold it and control it on every cycle. This is the feature which makes possible fast production.

Peck Tapping

The tap continuously moves in and out of the circle until the thread completes.

Form Tapping

In this process, no chips are formed because the material is not removed, rather it is placed somewhere within the hole. Form taps are used in this process.  It’s a relatively clean process because of no ships.

What is the Formula for Tapping in CNC?

There are two formulas which are used for Tapping in CNC. One for feed rate and the second to find spindle speed.

Spindle Speed

Here,

SFM is the cutting speed, and D is the diameter of the tap.

Feed Rate

RPM is the spindle’s speed and TPI is the threads per inch. If the spindle moves with 1000 RPM to create 20 TPI, then the feed rate will be 50 IPM.

Cutting speed

CNC Tapping G Code Explained

CNC (Computer Numerical Control) machine works by programming i.e. G-Code. G-code uses its commands to control the functions of the CNC machines. According to these codes, the tap can reverse to its original position automatically and rotate clockwise.

CNC Lathe Tapping Cycle Program

Common Applications for CNC Tapping

Since CNC tapping is an automatic machine, it is easy to work with it. It produces high-quality and precise threads within the holes which is why it is widely used in automotive (engine blocks cylindrical heads, transmission housing etc.), aerospace (landing gear, jet engine components and avionics), electronics and industrial equipment industry etc. Its applications show how much CNC tapping is important in manufacturing areas.

How to Improve Performance with CNC Tapping

Many things can be optimized to improve CNC tapping performance. For instance, the selection of taps is very important. Orientation and hold of the workpiece are important to consider while working. Accurate feed rate and spindle speed improve performance. Enough lubrication is also important for performance.

China CNC Tapping Services Supplier: Tuofa CNC Machining

We provide you with the best services for CNC tapping. To get the precise and accurate size of threads within the screws, bolts and nuts etc. visit Toufa CNC Machining. We will deliver our services within the delivery time with the best prices.

FAQ

What is the Difference Between Tapping and Drilling?

Drilling is done to make holes within the workpieces. Then tapping is used to make threads within these holes. These processes are used in making nuts and screws etc.

CNC Tapping vs. Rigid Tapping

These both are tapping processes and can be performed using the CNC machine. In Rigid Tapping process, the synchronization between the spindle rotation and z-axis movement does the job of making threads. These threads are of high quality.

CNC Tapping vs. Threading?

If you need threads within the holes of parts let’s, say in nuts, use the tapping process. In this process, taps are used for tapping.

There are different threading standards available which are used for threading. It is specifically used for cylindrical objects such as bolts, rods etc. by using dies of required designs and sizes.

What are tap and die sets used for?

The required material is placed into the die set, and the shape of that die takes that material at the end. A tap is a tool which is used for tapping i.e. making threads within the holes.