Have you ever encountered these questions: How is the drill made? What problems will be encountered in drill machining? About the bit material and its properties? What do you do when the drill fails?......

1 Process

1.1 Process

According to the diameter and total length of the designed bit, an alloy rod cutter or a wire-cutting device can be used for fixed-length machining.

Two flat ends of cut rods of fixed length could be used on hand tool grinders.

Chamfering or perforating on the ground end faces of alloy rods to prepare for grinding the outer diameter and shank of the bit. It depends on whether the cylindrical grinding jig is positive or negative.

Processing the outer diameter of the drill bit, the outer diameter of the cavitation part and the shank part on a high precision cylindrical grinder to ensure the design requirements of the cylindrical diameter, circular runout, surface finish and so on.

In order to improve the machining efficiency in numerical control grinder, chamfering the drill tip can be used before the numerical control grinder is applied to the alloy rod material. For example, the chamfering Angle can be used to rough grind to 142°.

Clean the alloy rod material after chamfering, and transfer to the process of numerical control grinder. All parts of the bit are processed on the five-axis numerical control grinder.

If the drill bit needs to be improved in the size of the sink and the surface finish, it can be polished with a wool wheel and welcome before or after the fifth step. In this case, it must be processed in more steps.

If there are something under the company's brand and the bit's size, a laser is made to mark it.

❾ will carved bit pack, then delivery to professional coating company for coating

Note:

1. Such as drill chip slot, or spiral or straight groove, this step also includes negative chamfering around the edge; Then machining the cutting edge of the drilling tip, including the drilling tip backlash part and the drilling tip Angle part; Then the back part of the bit edge is processed to grind out a certain amount of drop to ensure that the outer diameter part of the bit edge and the contact surface of the workpiece hole wall are controlled in a certain proportion.

2. For the machining of the negative chamfering edge of the drill tip, it is divided into CNC grinding machine processing or manual processing, which varies according to the different processes of each factory.

1.2 Processing problems

When machining the outer part of the bit in an outer grind, pay attention to whether the fixture is invalid and cool the alloy rod sufficiently. Keep a good habit of measuring the outer diameter of the drill tip.

The drills were processed on a CNC grinder. Two steps of rough finishing should be separated to avoid potential hot cracks caused by too much grinding, which could affect the service life of the tool.

Handling tools with reasonably designed material plates to avoid cutting edge damage caused by cutting tools bumping against each other.

Make timely cutting treatment with oil stone for blackened diamond grinding wheel.

Note: The processing technology is different according to the processed material/equipment/working condition. The above process arrangement only represents the author's personal opinion and is for technical communication only

2. Drill material

2.1 High speed Steel

High speed steel (HSS) is a kind of tool steel with high hardness, high wear resistance and high heat resistance, also known as high speed tool steel or front steel, commonly known as white steel.

High speed steel tool is a kind of tough than ordinary tools, easier to cut the tool, high speed steel than carbon tool steel has better toughness, strength, heat resistance, the need for UG programming Q group 45867470 cutting speed than carbon tool steel (iron carbon alloy) much higher, so named high speed steel; The performance of hard alloy is better than that of high speed steel, and the cutting speed can be improved by 2-3 times.

characteristic

High speed steel red hardness can reach 650 degrees.

High speed steel has good strength and toughness, sharp cutting edge and stable quality after grinding. It is generally used to manufacture small and complex cutting tools.

2.2 Hard alloy

Carbide bit material is mainly composed of tungsten carbide and cobalt, which account for 99% of all components, 1% is other metals, so it is called tungsten steel (hard alloy). Tungsten steel is a sintered composite consisting of at least one metal carbide. Tungsten carbide, cobalt carbide, niobium carbide, titanium carbide, tantalum carbide are common components of tungsten steel. Carbide components (or phases) typically have grain sizes ranging from 0.2 to 10 microns, and carbide grains are held together using metal binders. Bonded metal is generally iron group metal, commonly used is cobalt, nickel. Hence the tungsten-cobalt, tungsten-nickel, and tungsten-titano-cobalt alloys. Tungsten steel bit material sintering molding is to press powder into billet, and then into the sintering furnace heating to a certain temperature (sintering temperature), and maintain a certain time (holding time), and then cooling down, so as to obtain the required performance of tungsten steel material.

Features:

Hard alloy red hardness can reach 800-1000 degrees.

The cutting speed of cemented carbide is 4-7 times higher than that of high speed steel. High cutting efficiency.

The disadvantages are low bending strength, poor impact toughness, brittleness, low impact and vibration resistance.

3 Application problems/measures

3.1 Drilling tip wear

Reasons:

1. The workpiece will move downward under the drilling force of the bit and spring back after the bit is drilled through.

2. Insufficient rigidity of machine tool.

3. Drill material is not strong enough.

4. The drill bit is bouncing too much.

5. The clamping rigidity is not enough and the bit slips.

Measures:

1. Reduce cutting speed.

2. Increase the supply

3. Adjust cooling direction (internal cooling)

4. Add a chamfer

5. Check and adjust the coaxiality of the bit.

6. Check whether the rear Angle is reasonable.

3.2 Broken ligament blade

Reasons:

1. The workpiece will move downward under the drilling force of the bit and spring back after the bit is drilled through.

2. Insufficient rigidity of machine tool.

3. Drill material is not strong enough.

4. The drill bit is bouncing too much.

5. The clamping rigidity is not enough and the bit slips.

Measures:

1. Choose a drill with a larger back cone.

2. Check the run-out range of spindle bit (< 0.02mm)

3. Drill the top hole with a predetermined heart drill.

4. Use a stiffer drill bit, hydraulic chuck with neck sleeve or heat shrink kit.

3.3 Cumulative chipping

Reasons:

1. Caused by the chemical reaction between cutting materials and workpiece materials (low carbon steel with higher carbon content)

Measures:

1. Improve lubricant, increase oil or additive content.

2. Improve cutting speed, reduce feed rate and reduce contact time.

3. If drilling aluminum, use a surface polished uncoated drill bit.

3.4 Breaking Knife

Reasons:

1. The spiral groove of the drill is blocked by cutting, and the cutting is not discharged in time.

2. When the hole is drilled quickly, the feed rate is not reduced or the motor is changed to manual feed.

3. When drilling soft metals such as brass, the rear Angle of the bit is too large, and the front Angle is not polished, so that the bit can screw in automatically.

4. The drilling edge is too sharp, resulting in the phenomenon of collapsing edge, and the tool can not be quickly retreated.

Measures:

1. Shorten the tool replacement period.

2. Improve the installation and fixing, such as increasing the supporting area and increasing the clamping force.

3. Check the spindle bearing and sliding groove.

4. Use high precision shank, such as hydraulic shank.

5. Use tougher materials