Replaceable Bits: Characteristics And Selection

Replaceable bits are products that have been applied and developed since 1990s.

When machining parts, especially multiple hole positions, when the cemented carbide drill tip on the drill bit is worn, it can be easily replaced without removing the tool body of the drill bit from the tool handle or machine tool spindle.

The concept of replacing cemented carbide drill tips on the steel cutter body of the drill bit also led to the development of replaceable head milling cutters and modular reaming systems, and also achieved good machining results.

The structure of replaceable bit is shown in Fig. 5-20.

replaceable bit

Fig. 5-20 replaceable bit

(1) Characteristics and selection

The replaceable bit has the following characteristics:

(1) Reduce tool body replacement time and tool management cost.

(2) Reduce the cemented carbide materials used in the cutter body.

(3) Longer tool life and predictability of hole machining.

(4) Reduce bit inventory.

(5) It eliminates the fluidity of regrinding, returning and backup tools required for the drill bit.

(6) The tool loading time is greatly shortened, because the drill point is replaced on the machine tool and tool handle, and there is no need to pre adjust, compensate and set the tool.

The correct selection of drill bit type should meet the requirements of drilling size, tolerance, surface roughness and economy.

For the machining with aperture less than φ12.7mm, considering the machining accuracy and machining performance, the integral cemented carbide bit is still the recommended solution.

For machining (especially rough machining) with an aperture greater than φ25mm, it is recommended to use indexable blade drills.

When machining holes with an aperture larger than φ25 ~ φ51mm on high-power machine tools, it is particularly effective to use indexable blade drills.

When the power of the machine tool is enough, the composite drill can be used for the machining of large holes.

In the drilling process with the aperture range of φ12.7 ~ φ25.4mm, the replaceable bit has become a common and better choice, because this kind of bit can achieve the comprehensive competitive advantage of high hole processing accuracy and cost-effectiveness.

Cemented carbide drill tips have the characteristics of optimizing the shape design of drill tips according to the workpiece materials and processing requirements, and usually do not regrind, so each drill tip replaced is new, and its processing performance is exactly the same as all other new drill tips.

(2) Typical product introduction

1. Replaceable bit B401X

(1) Product introduction.

Walter Color Select colors the indexable blades according to the commonly used ISO colors, and the cutting material is named after these colors, so it can be classified accurately, so the risk of blade confusion is reduced.

The improved micro hardness and toughness can improve the performance of cutting materials. At the same time, the thickness of the coating is thicker than the previous cutting materials. Using a special process to carry out mechanical post-treatment on the coating, the tool life is increased by 95% on average compared with the previous cutting materials, thus significantly reducing the assembly cost.

B401X (see Fig. 5-21) is especially suitable for processing through holes and blind holes, precision drilling, packaging drilling and drilling up to 10 times the diameter.

The possible application fields of WPP45C for B401X include general machinery industry, pressure vessel / heat exchanger (pipe and diaphragm) manufacturing, automobile industry and mold industry.

replaceable bit B401X

Fig. 5-21 replaceable bit B401X

(2) Application examples

1) Processing workpiece: support.

2) Workpiece material: S355M(1.8823)St52, tensile strength: Rm=550n/mm ².

3) Machine tool: Heller MCP-H 400, machine tool power 34Kw.

4) Handle: DIN69871 SK50.

5) Drill bit: B4015.F20.17,0.Z02.51R,d=17mm.

6) Blade:P6001-D17,0R WPP45C.

7) Cooling pressure: 1.5 ~ 2MPa.

8) Cutting parameters: vc=96m/min, n=1800r/min, f=0.27mm/r, vf= 490m/min, hole depth L=50mm.

9) Processing effect: good surface quality, blade life 130min.

2. Drillforcemeister large diameter drillable bit

(1) Product introduction.

Drillforcemeister large diameter drillable bit (see Fig. 5-22) is an innovative solution, which helps to improve processing parameters and aperture accuracy, achieve excellent aperture surface quality, and greatly reduce machine downtime.

Behind the innovation, the geometric structure and material of the bit blade are optimized, which will help to achieve higher processing efficiency.

DrillForceMeister large diameter drillable bit

Fig. 5-22 DrillForceMeister large diameter drillable bit

(2) Product features

1) The blade has a unique one-way locking structure.

2) The high repeated positioning accuracy ensures the minimum runout of the drill bit.

3) The blade can be removed from the knife body without completely loosening the screw.

4) The drill blade can be quickly replaced on the machine tool, greatly reducing the downtime.

5) The contact surface of the fastening screw guides the locking force to the required direction to ensure the locking effect of the blade.

6) The optimized blade structure realizes smooth chip removal and excellent chip shape.

7) The geometric structure design of drill angle can reduce the burr during drilling.

8) Diameter range: φ 26.0~ φ 41.0mm, length diameter ratio L/D=3 ~ 5.

(3) Application examples

1) Workpiece Name: annular part.

2) Workpiece material: S55C.

3) Application: drill through holes.

4) Machine tool: vertical machining center, BT50 handle.

5) Cutting fluid: water soluble (internal cooling).

6) Drill pipe: TIS260F32-5.

7) Blade: SMP260 AH725.

8) Cutting parameters: vc=100m/min, f=0.35mm/r, hole depth L=150mm.

9) Cutting effect: the service life of the tool is increased by 40m, which is 20% higher than that of the original drill.

3. Drillmeister replaceable head drill

(1) Product introduction.

Tecolo drillmeister bit (see fig. 5-23) integrates the production efficiency of the overall bit and the flexibility of the indexable shallow hole drill.

It adopts a unique geometric structure design of quick change of the bit, which greatly improves the production efficiency of users and reduces the production cost.

Drillmeister series products are applicable to the fields of automobile, power generation, oil and gas, construction and general processing.

They have excellent performance in processing a variety of materials such as low carbon steel, alloy steel, stainless steel, cast iron, aluminum alloy, titanium alloy and heat-resistant alloy.

drillmeister replaceable bit

Fig. 5-23 drillmeister replaceable bit

(2) Product features

1) Wedge locking structure provides excellent locking rigidity and reliability, and also simplifies the setting time of the blade.

2) The optimized drill point geometry has excellent chip removal performance.

3) The geometric structure of drill angle is designed to reduce burr during drilling.

4) The optimized honing size and drill point geometric angle prevent machining vibration.

5) It can process the same high-precision aperture as the hardened drill bit.

6) Tidcf series chamfering cutter body combines drilling and chamfering to reduce processing time.

7) No grinding and less inventory, reducing processing costs.

8) The diameter increases by 0.1mm from φ10.0mm, and the maximum diameter is φ25.9mm.

9) The aspect ratio is 1.5, 3, 5, 8 and 12.

(3) Application examples

1) Workpiece Name: diaphragm (see Fig. 5-24).

processed workpiece - diaphragm

Fig. 5-24 processed workpiece – diaphragm

2) Workpiece material: SUS316.

3) Application: drill through holes.

4) Machine tool: vertical machining center BT50 tool handle.

5) Cutting fluid: internal cooling + external cooling.

6) Drill pipe: TIDC160C16-5.

7) Drill point: DMP167 AH725.

8) Cutting parameters: vc=100m/min, f=0.28mm/r, vf=961mm/min, hole depth L=55mm.

9) Cutting effect: the tool life is increased by 1.2 times.

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