The use and safety management of drill bit grinder grinding wheel

From the transportation and storage of the grinding wheel, the inspection before use for the installation, dressing of the grinding wheel, and the operation of the grinding machinery, any negligence of any link will bury a hidden danger to the drill bit grinder.

Grinding wheel inspection

The grinding wheel with cracks and other defects is absolutely not allowed to use. The grinding wheel must undergo strict inspection before it is used.

(1) Visual inspection is to observe whether there are cracks or damages on the surface of the grinding wheel directly with the naked eye or with the aid of other instruments.

(2) Sound inspection is also known as percussion tests. The inspection method is to beat the grinding wheel with a small wooden hammer. The normal grinding wheel is crisp. If the voice is active and hoarse, it will be problematic.

Grinding wheel device

Whether the grinding wheel matches the spindle size.

(1) Check whether the characteristics of the grinding wheel meet the requirements of use.

Do not press hard. The matching gap between the grinding wheel inner diameter and the spindle and chuck is appropriate.

(2) Assemble the grinding wheel freely to the spindle of the grinding wheel. Prevent too large or too small. The matching surface should be clean and free of debris.

(3) The chuck of the grinding wheel should be symmetrical. Abundant contact with the front of the grinding wheel and stable clamping prevented the two sides of the grinding wheel from deformation or even fragmentation due to unbalanced force.

(4) A certain thickness of flexible data lining (such as asbestos rubber board, elastic cardboard or leather) should be inserted into the chuck and the end face of the grinding wheel to make the chuck clamping force evenly distributed.

(5) The tightness of the grinding wheel should be tightened enough to make the grinding wheel do not to slide.

Balancing test of grinding wheels

For example, the imbalance of the grinding wheel is due to the fact that the center of gravity of the grinding wheel does not coincide with the axis of rotation. The reasons are the defects of grinding wheel manufacture and installation, uneven density of grinding wheel, non-parallel end face, geometric shape or concentricity error of inner and outer holes, eccentricity of grinding wheel device and so on. When an unbalanced grinding wheel rotates around high speed, the centrifugal force which forces the grinding wheel to deviate from the axis will occur, thus causing the vibration of the grinding wheel. The results not only affect the grinding quality, but also accelerate the wear and tear of the main shaft bearing of the grinding wheel. When the centrifugal force exceeds the allowable range of the grinding wheel strength, the grinding wheel will be broken.

Dressing of grinding wheels

To prevent passivation, blockage and distortion of grinding wheel, regular dressing can make grinding wheel adhere to good grinding performance and correct geometry. The usual dressing tool is diamond pen.

Storage and transportation of grinding wheels

(1) It can not be subjected to strong vibration and impact. The wheels are in transportation and storage. It is not permitted to move the wheel when handling, so as to avoid cracks and surface to damage.

(2) Signs of characteristics of wheel and safety speed must not be smeared or damaged at will.

(3) The storage time of grinding wheel should not exceed the validity period of grinding wheel. If the storage time exceeds one year, it must be qualified after the rotation test is used.

(4) Grinding wheel storage site should be kept dry. Prevent mixing with other chemicals. Prevent wheel dampness, low temperature, overheating and harmful chemicals from erosion.

(5) Grinding wheels should be based on specifications, shapes and sizes. Prevent overloading damage or cause improper grinding wheel deformation.

4 guidelines for how to precisely grind drill bits

1. Correctly select grinding wheel (Including type and model)
2. For new drill bits or cutting tools, first step to check and record the main geometric parameters, especially record re-grinding situation of chamfering blade, chamfering, and chisel edge of drill bits or cutting tools.
3. Input the parameter data of grinding wheel, then input data of grinded drill bits or cutting tools.
4. To detect the main parameters of drill bits or cutting tools after grinding, and compare with grinding before, re-grinding again if there are different.

For more drill bit grinding guidelines, please feel free to contact drill bit grinding expert (PURROS).

Safety operation procedure for semi-automatic drill bit sharpening machine

Safety operation procedure for semi-automatic drill bit grinder

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The grinding wheel should be returned first, then the drill bit is mounted on the drill bit to adjust the Angle.
When the drill bit turns normally, the machine meshes well and can be grinded. The protective cover should be complete and normal before grinding.
Manual feed should be carried out slowly, especially when the grinding wheel is in contact with the drill bit.
After the drill bit grinding is finished, exit the grinding tool and stop the lathe. The drill bit can be unloaded until it is stationary.
After the drill bit is loaded, the wrench should be removed in time and not allowed on the chuck.
When dressing the grinding wheel, put the feed handle in the neutral position, and after the grinding wheel turns normally, the it can be redressed. The fixture should be fastened, the feed should be slow; Wear protective glasses, the head should be avoided, the protective cover should be installed, the dust collection device should start. Replacement of new grinding wheel shall comply with the general safety regulations of the grinder.
The workpiece should be put in place to prevent injuries.

PURROS Drill bit grinder – Grinding wheel

abrasive grain

The grinding wheel of different materials is suitable for grinding different kinds of cutting tools. Different parts of the tool need to be used in different sizes to ensure the best combination of blade protection and processing efficiency.

Alumina: used for grinding HSS drill bit. The grinding wheel is cheap and easy to be modified into different shapes for grinding complicated knives.

Silicon carbide: used to modify the CBN wheel and diamond wheel.

CBN (cubic boron carbide) : used for grinding HSS drill bit.

Diamond: used for grinding HM drill bit.

PURROS drill bit grinder with best grinding wheel.
Drill’s Grinding Wheel, 4.5 grinding wheel, 3 grinding wheel, 4 grinding wheel, 6 grinding wheel, 7 grinding wheel, 8 grinding wheel

Shape of grinding wheel

In order to facilitate the grinding of different parts of the tool, the grinding wheel should have different shapes. The most common ones are:

Parallel grinding wheel (1A1): grinding top Angle, outer diameter, back, etc.

Disc wheel (12V9,11V9): grinding spiral groove, the main of milling cutter, cutting edge, trimming blade, etc.

After a period of use, the grinding wheel needs to be modified (including plane, Angle and rounded Angle R). The grinding wheel must always be cleaned with the cleaning stone to clean up the chips to improve the grinding ability of the grinding wheel.

Five different types of cylindrical grinding

There are 5 different types of round grinding: inside diameter grinding (ID grinding), outside diameter grinding (OD grinding), plunge grinding, creep feed grinding, as well as centerless grinding.

Inside diameter grinding

ID grinding is grinding happening on the within an item. The grinding wheel is constantly smaller sized compared to the size of the item. The things is kept in location by a collet, which likewise turns the things in position. Equally as with OD grinding, the grinding wheel and also the item turned in other instructions offering reversed instructions get in touch with of both surface areas where the grinding occurs.See likewise ID Grinding.

Outside diameter grinding

OD grinding is grinding taking place on exterior surface area a of an item in between the facilities. The facilities are end systems with a factor that enable the challenge be revolved. The grinding wheel is likewise being turned parallel when it can be found in call with the things. This successfully suggests both surface areas will certainly be relocating other instructions when call is made which enables a smoother procedure and also much less possibility of a repress.Continue reading→

Fine Sharpening Lathe Tool

(1)Fine Sharpening Flute: In order to make the shape of flute more precision, and surface roughness is finer than before, so flute should be fine sharpened after rough sharpening. The sharpening method is the same as rough sharpening.

(2)Sharpening Negative Chamfering: Negative Chamfering is commonly sharpened by end of grinding wheel, the granularity between 100# to 200#. The sharpening method as follow the figure :

Negative Chamfering

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The Standard Sharpening Method of Lathe Tools

The Steps of Sharpening Lathe Tool

Step 1: Sharpening the major flank face, at the same time, sharpening lip relief angle;
Step 2: Sharpening the minor flank face, at the same time, sharpening end relief angle;
Step 3: Sharpening the fake face, at the same time, sharpening point angle;
Step 4: Sharpening remained faces and the tip;

The Methods of Sharpening Lathe Tool

Now, PURROS Machinery takes the rough grinding carbide alloy cutter as an example, to illustrate the method of cutting tool sharpening.

1. Rough sharpening the major flank face and the minor flank face, at the same time, major angle of declination, major lip relief angle, minor angle of declination, and minor lip relief angle also has sharpened. The angle of major lip relief angle and minor lip relief angle by rough sharpening should be bigger than requested. View Figure:

Lip Relief Angle of Shank

(a) Lip Relief Angle, behind the major flank face of shank
(b) Lip Relief Angle, behind the minor flank face of shank

2. Rough Sharpening Rake Face: Rake Face and Flute are sharpened at the same time, before flute is sharpened, used the end face of grinding wheel to rough sharpen, to obtain the necessary angle and surface roughness.

3. Sharpening Flute: Flute can be sharpened by edge of flat grinding wheel, as Figure shows the sharpening method. Generally, the position of rough sharpening should be began half of between flute and drill bit tip.

Rough Sharpening Flute

(a) Sharpening Down (b) Sharpening Up

The Notes of Lathe Sharpening by hand.

The Notes of Lathe Sharpening

Please note that operator should stand on the side of the lathe tool grinder, to prevent hurtful from debris if the grinding wheel is broken.
Keeping enough distance to hold the shank of lathe tool between hands, to tighten the waist with two elbows to reduce the shaking of the lathe tool sharpening.
During sharpening lathe tool, please place the lathe tool on the horizontal center of the grinding wheel, and the tip of the lathe tool is slightly upward about 3°-8°, when the lathe tool touches the grinding wheel that the lathe tool should be moved around horizontally.
During sharpening major flank face, the lathe tool shank should be shifted an angle to the left as major cutting edge angle; during sharpening minor flank face, the lathe tool shank should be shifted an angle to the right as minor cutting edge angle.
During sharpening arc of the tip, generally, holding the tip of lathe tool with left hand as a fulcrum, and at the same time, moving the shank of lathe tool with right hand.

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How to select the grinding wheel before sharpening the lathe tools？

How to select the grinding wheel?

Grinding wheel

Rough grinding lathe tool should be selected the grinding wheel with smaller abrasive grains, on the contrary, fine grinding lathe tool should be selected the grinding wheel with bigger abrasive grains. When sharpening lathe tool of HHS, it should be used the granularity between 46 and 60, or soft aluminum oxide grinding wheel. When sharpening carbide-tipped lathe tool, it should be used the granularity between 60 and 80, or soft Sic grinding wheel. Tips: Do not confuse the two different grinding wheels.

How does the twist drill bit sharpen can be more sharper?

The twist drill bit is the most commonly used cutting tool, the twist drill bit wants to be sharpened, so pay attention to some points below to:

For mechanical processing, twist drill bit is the most important of drilling tool, in all itsstructure simplicity,but it’s not easy to sharpen it right. The keypoint is to master the sharpening methodsand skills.If the method is mastered, the problem will be solved.Let me introduce the manual grinding of twist drill bit.

Usually, the point angle of twist drill bit is about 118°，it could also be treated 120°, the sharpening skills as follows:Continue reading→

Grinding wheel inspection

Grinding wheel device

Balancing test of grinding wheels

Dressing of grinding wheels

Storage and transportation of grinding wheels