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Common Problems Encountered With Tap Tapping In Injection Molds

Common Problems And Solutions During The Tapping Process Are Listed Below

Thread Stop Gauge Is Not Enough

Causes And Measures

Improper selection of taps

•Select the appropriate tap (based on material, hole pattern, thread tolerance, etc)

Speed too high

•Reduce the speed

•Improve the coolant quality and improve the cooling and lubrication effects

Generate cutting tumor

•Replace with new taps

•Use coated taps

•Improve coolant quality and improve cooling and lubrication effects

•Remove cutting nodules and damaged cutting teeth.

Chip blocking

•Select taps with more suitable cutting parameters (including spiral grooves, cutting angles, etc) •Select group taps if necessary

The tap has burrs

•Carefully remove burrs

Inaccurate positioning and clamping

•Use the tapping fixture with automatic axial and radial adjustment

•Check the coaxiality of the bottom hole, tap and spindle

Tapping feed is unstable

•Improve tapping procedures

•Check machine tool drive screws

•Use tapping fixtures with length compensation

Improper tap grinding

•Try to ensure that the cutting parameters of the reground tap are consistent with those of the new tap.

Axial pressure is too large

•Adjust tapping axial pressure

•Use tapping fixture with length compensation function

Rotten And Rough Teeth

Causes And Measures

Improper selection of taps

•Select the appropriate tap (based on material, hole pattern, thread tolerance, etc)

Speed too high or too low

•Select the recommended tapping speed

Severe chip edge

•Replace with new taps

•Use coated taps

•Improve coolant quality and improve cooling and lubrication effects

•Remove cutting nodules and damaged cutting teeth

Chip blocking

•Select taps with more suitable cutting parameters (including spiral grooves, cutting angles, etc) •Select group taps if necessary

The tap has burrs

•Remove burrs

Bottom hole is too small

•Use reasonable bottom hole size

Insufficient cooling and lubrication

•Use reasonable cutting fluid

•Appropriately increase the supply of cutting fluid

The cutting amount of a single tooth of the tap is too large

•Appropriately increase the length of the cutting tap

•Switch to group taps

The Thread Is Blocked

Causes And Measures

The tap is severely worn

•Replace with new taps

Improper selection of taps

•Select the appropriate tap (based on material, hole pattern, thread tolerance, etc)

Thread profile parameter error

•Switch to a tap with better performance

•Use a tapping fixture with length compensation function

Premature Tap Wear

Causes And Measures

Cutting edge hits hole bottom

•Control the bottom hole and effective thread depth

•Use E-type or even F-type cutting edge when necessary

No coating or poor coating quality

•Use appropriate coated taps based on the properties of the tapping material

Tap Life Is Short

Causes And Measures

Annealing during tap regrinding

•Change grinding parameters (grinding wheel model, rotation speed, coolant, etc)

Material hardened severely during drilling

•Replace the drill bit in time

•Adjust drilling parameters (speed, feed, etc)

•Anneal the material before tapping

Tap Tapping

Analysis And Summary Of 10 Major Problems Of Tap Breakage

Tap Quality Is Poor

Main materials, CNC tool design, heat treatment conditions, processing accuracy, coating quality, etc. For example, the size difference at the transition point of the tap cross section is too large or the transition fillet is not designed, resulting in stress concentration, and it is easy to break at the stress concentration point during use.

The cross-sectional transition at the junction of the shank and the blade is too close to the welding port, resulting in complex welding stress superimposed on the stress concentration at the cross-sectional transition, resulting in a large stress concentration, causing the tap to break during use. For example, improper heat treatment process.

During the heat treatment of taps, if there is no preheating before quenching and heating, if the quenching is overheated or overburned, if the tap is not tempered in time and if it is cleaned too early, it may cause cracks in the tap.

To a large extent, this is also an important reason why the overall performance of domestic taps is not as good as imported taps.

Countermeasures: Choose high-quality and reliable tap brands and more suitable tap series.

Improper Tap Selection

For tapping parts that are too hard, high-quality taps should be selected, such as cobalt-containing high-speed steel taps, carbide taps, coated taps, etc. In addition, different tap designs are used in different working situations. For example, the number, size, angle, etc. of the chip removal grooves of the tap have an impact on the chip removal performance.

For difficult-to-machine materials with high hardness and good toughness, such as precipitated stainless steel and high-temperature alloys, the tap may break due to its insufficient strength and inability to withstand the cutting resistance of tapping.

In addition, the problem of the mismatch between taps and processed materials has attracted more and more attention in recent years. In the past, domestic manufacturers always thought that imported ones were better and more expensive, but in fact they were more suitable.

As new materials continue to increase and are difficult to process, in order to meet this need, the variety of tool materials is also constantly increasing. This requires selecting the appropriate tap product before tapping.

Countermeasures: Use taps made of high-strength materials (such as powdered high-temperature steel, etc.) to increase the strength of the tap itself; at the same time, improve the surface coating of the tap to increase the surface hardness of the wire; in extreme cases, even manual tapping may be a feasible method.

Excessive Tap Wear

Another very common situation is that after the tap processes several threaded holes, the cutting resistance increases due to excessive wear of the tap, causing the tap to break.

Countermeasures: First of all, it is recommended to use Sentai Inge V-handle, which will significantly delay the wear of the tap, thereby increasing the service life of the tap; at the same time, using high-quality tapping lubricant can also effectively delay the wear of the tap; in addition, use a thread gauge (T /Z) can easily judge the tap condition.

Axial Synchronization Error

During the tapping process of the machining center, a large number of broken taps are caused by errors in the synchronization between the machine tool spindle rotation and axial feed, which increases the axial tension (or pressure) on the tap, causing the tap to break.

The synchronization error is almost impossible to completely avoid in rigid tapping of a machining center (or CNC lathe), especially when the tap is retracted (reversed).

Countermeasures: Use Sentai Inge V handle, which completely solves the problem of axial synchronization error compensation in rigid tapping.

Difficulty In Chip Breaking And Chip Removal

For blind hole tapping, a spiral groove rear chip discharge tap is usually used. If the iron chips are wrapped around the tap and cannot be discharged smoothly, the tap will be broken, and a large number of processed materials (such as steel, stainless steel, and high-temperature alloys, etc.) are tapped. Machining is often difficult to break chips.

Countermeasures: First consider changing the helix angle of the tap (usually there are several different helix angles to choose from) to try to allow the iron chips to be removed smoothly; at the same time, adjust the cutting parameters appropriately to ensure that the iron chips can be removed smoothly; if necessary Variable helix angle taps can be used to ensure that iron chips can be discharged smoothly.

The Bottom Hole Diameter Is Too Small

For example, when processing M5×0.5 threads of ferrous metal materials, a cutting tap should be used to drill a bottom hole with a drill bit with a diameter of 4.5mm. If a 4.2mm drill bit is mistakenly used to drill a bottom hole, the portion required to be cut by the tap during tapping will inevitably increase. , causing the tap to break.

It is recommended to choose the correct bottom hole diameter according to the type of tap and the material of the tapping piece. If there is no completely suitable drill bit, you can choose a larger one.

Issues With The Material Of The Tapping Piece

The material of the tapping piece is impure, and there are local hard spots or pores, causing the tap to lose balance instantly and break.

The Machine Tool Does Not Meet The Accuracy Requirements Of The Tap.

Machine tools and clamping bodies are also very important, especially for high-quality taps. Only machine tools and clamping bodies with a certain degree of precision can bring out the performance of taps.

The common thing is that the concentricity is not enough. When tapping starts, the starting position of the tap is incorrect, that is, the spindle axis is not concentric with the center line of the bottom hole, and the torque is too large during the tapping process, which is the main reason for the tap to break.

Cutting Fluid And Lubricating Oil Are Of Poor Quality

Many domestic companies have begun to pay attention to this. Many companies that have purchased foreign cutting tools and machine tools have a very deep experience.

When there are problems with the quality of cutting fluids and lubricants, the quality of processed products is prone to burrs and other defects. At the same time, the service life There will also be a big reduction.

Cutting Speed And Feed Are Unreasonable

When processing problems occur, most domestic users reduce the cutting speed and feed rate. This reduces the pushing force of the tap, and the precision of the thread produced is greatly reduced. This increases the roughness of the thread surface and reduces the thread quality.

There is no way to control the hole diameter and thread accuracy, and problems such as burrs are of course inevitable. However, if the feed speed is too fast, the excessive torque caused may easily cause the tap to break.

The cutting speed during machine tapping is generally 6-15m/min for steel materials; 5-10m/min for quenched and tempered steel or harder steel materials; 2-7m/min for stainless steel; and 8-10m/min for cast iron. For the same material, the smaller the tap diameter, the higher the value, and the larger the tap diameter, the lower value.

Contact Person: Alex Chu
WhatsApp/ WeChat: 0086 18968677763
Email: sc10@solidcomould.com
Website: www.solidcomould.com

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