Nakanishi NR-303 User manual

NR-303
Spindle
1. CAUTIONS FOR HANDLING AND OPERATION
■Read these warnings and cautions carefully and only use in the manner intended.
■ These warnings and cautions are intended to avoid potential hazards that could result in personal injury or
damage to the device. These are classified as follows in accordance with the seriousness of the risk.
Thank you for purchasing this spindle. This spindle is designed for grinding, small diameter drilling and milling.
Control unit, electric motor and air line kit are required to drive this spindle. Please read this Operation Manual
carefully before use.
2. FEATURES
①The spindle housing is made from precision ground, hardened, stainless steel (SUS)with an outside diameter
of ȭ22.8mm.
②This spindle utilizes precision bearing. Designed to minimize the radial and axial plays.
③Various sizes of collet chucks are available CHK 0.5 mm - 6.35mm.
Standard collet chuck is CHK 3.0mm or CHK 3.175mm. (For U.S. market CHK-3.175mm.)
Class Degree of Risk
WARNING
A safety hazard could result in bodily injury or damage to the device if the
safety instructions are not properly followed.
CAUTION A hazard that could result in light or moderate bodily injury or damage
to the device if the safety instructions are not followed.
CAUTION
①Do not drop or hit the spindle, as shock can damage to the internal components.
②Do not connect this spindle to the air motor AM-600. This cause damage to the spindle, or
brekage by heat generation.
③Be sure to clean the collet chuck and chuck nut, the inside of the spindle before replacing the
tool. If ground particles or metal chips stick to the inside of spindle or the collet chuck, damage
to the collet chuck or spindle can occur due to the loss of precision.
④When cleaning a spindle, stop the motor and remove dirt with a brush or a cloth. Do not blow
air to a dust proof cover area (refer to Section 3 - 2 "Outside view") with compressed air,
foreign particles or cutting chips might get into the ball bearing.
⑤Always clean the tool shank before installing the tool in the spindle.
⑥Use only tools with shank diameters within the tolerance of the selected collet chuck.
⑦Select suitable products or tools for all applications. Do not exceed the capabilities of the
spindle or tools.
⑧Carefully direct coolant spray to the tool. Do not spray directly on the spindle body.
⑨Stop working immediately when abnormal rotation or unusual vibration are observed.
Afterwards, please check the content of Section 10 "TROUBLESHOOTING".
⑩Always check if the tool, collet chuck or chuck nut are damaged before and after operating.
⑪If the collet chuck or chuck nut show signs of wear or damage, replace them before a
malfunction or additional damage occurs.
⑫After installation, repair, initial operation, or long periods of non operation, please refer to
Section 8. "BREAK-IN PROCEDURE" detailed in Table 1. When checking the spindle, no
vibration or unusual sound should be observed during rotation.
⑬Do not disassemble, modify or attempt to repair the spindle. Additional damage will occur to
the internal components. Service must be performed by NSK NAKANISHI or an authorized
service center.
⑭When using the spindle for mass production, please purchase the another spindle as a spare
in case of an emergency.
WARNING
①The spindle is not a hand tool. It is designed to be used on CNC machines or special purpose
machines.
②Do not touch the cutting tool while it is running. It is very dangerous.
③Wear safety glasses, dust mask and hearing protection, and use a protective cover around the
spindle whenever the spindle is rotating.
④Never touch the power cord with wet hands. This may cause an electric shock.
⑤Never operate or handle the spindle until you have thoroughly read the owner's manual and
safe operation has been confirmed.
1)To prevent injuries/damages, check the spindle and cutting tool for proper installation, then
operate the spindle.
2)Before disconnecting the spindle, always turn the control power off and turn the compressed
air supply to the control unit off. It is then safe to remove the spindle.
⑥When installing a tool, tighten the collet chuck correctly and check again the collet chuck and
chuck nut before use. Do not over tighten the collet chuck. This may cause damage to the
spindle.
⑦Do not use bent, broken, chipped, out of round or sub-standard tools as they can shatter or
explode. It shatters, it cracked, and the tool that bends and breaks disperses and it causing
injures. When using a new tool, rotate it in a low speed and increase speed gradually for safety.
⑧Do not exceed the maximum recommended allowable tool speed. For your safety, use speeds
below the maximum allowable speed.
⑨Do not apply excessive force. This may cause tool slippage, tool damage, injury to the
operator, loss of concentricity and precision.
CAUTION
Standard Accessories
・Collet Chuck ȭ3.0mm (CHK-3.0) or ȭ3.175mm (CHK-3.175)・・1pc.
(For U.S. market : ȭ3.175mm (CHK-3.175)
・Chuck Nut (K-265)・・1pc.
・Wrench (20 ×24)・・1pc.
・Wrench (12 ×14)・・2pcs.
・Operation Manual・・1set.
※The collet chuck and the chuck nut are attached to the spindle.
Collet Chuck (CHK- □□ )ȭ0.5mm - ȭ6.0mm in 0.1mm incremants and ȭ2.35mm, ȭ3.175mm, ȭ6.35mm.
Chuck Nut K-265
< Option >
3 - 2 Outside View
Fig. 1
4. CONNECTING TO THE MOTOR
Fig. 3
Dust Proof Cover Area
（106.8）
（16.9）76.6 13.3
-0.01
0
22.8
Ǿ
Ǿ15.9
17.1
Ǿ
Spindle Shaft
14
12
Loosen
14
12
Tighten
Cutting Tool
Chuck Nut
Tighten
Turn
20
20
Transmission Clutch
Fig. 2
5. CHANGING THE CUTTING TOOL
Align the threads on the front end of the motor and the rear end of the spindle, and turn the spindle clockwise. If
the drive shaft of the motor does not engage the drive dog on the spindle, the spindle could not be turned. DO NOT
FORCE. Turn the spindle back a few threads, rotate the cutting tool by hand to engage the drive shaft and the drive
dog, and make the final turns with wrench 20mm provided. (Fig. 2)
①Set the provided 12mm wrench on the spindle.
②Place the provided 14mm wrench on the chuck nut and turn it counterclockwise to loosen the collet chuck and
remove the cutting tool. (The first turn will loosen the chuck nut, but the tool will not release and turning will
become stiff. Keep turning through the stiffness and the collet chuck will open.)
③Inset the new cutting tool and tighten the collet chuck by turning clockwise.
CAUTION
OPERATION MANUAL OM-K0466E 001
3 - 1 Specifications
Model NR-303
Allowable Motor Speed 30,000min-1
Spindle Accuracy Less than 2μm
Weight 215g
3. SPECIFICATIONS AND DIMENSIONS
Make sure your hands and all interlocking parts of the spindle and motor are clean before
connecting the motor to the spindle. This is critical to prevent contaminants from entering the
motor or spindle.
Do not tighten the collet chuck without inserting a tool or dummy bur, as this will damage the
collet chuck, spindle or chuck nut, causing difficulty remove the collet chuck.

RECOMMENDATIONS
CAUTION
CAUTION
WARNING
7. INSTALLATION OF THE SPINDLE
In case of using the electric motor, when installing a spindle to a fixed base, make sure the fixed
base is grounded in order to avoid the risk of an electric shock.
・When installing a spindle, do not hit, drop or cause shock to the spindle. This may cause
damage to internal components and result in malfunctions.
・If the spindle is installed incorrectly, this will cause and damage to the spindle.
①When mounting the spindle, refer to the Clamping Area etched on the spindle. (Fig. 6)
22 35
(Clamping Area)
Fig. 6
②The installation shown in Fig. 7 is the recommended installation method. If this is not possible, install as show
in Fig. 8. Do not allow set screws to come directly in contact with the spindle body as show in Fig 9, as this will
result in damage to the spindle housing and internal components.
When mounting, never clamp directly over the bearings, as this will result in bearing damage.
Fastening Bolt
Split Bushing
Buching Split
Split Type Holder
㱢D
㱢D
㱢D
Slit
Fastening Bolt Fastening Bolt
Fastening Bolt
Fig. 7 Fig. 8 Fig. 9
・Cautions when tightening the securing bolt
Do not over tighten the bolt. This may cause damage to spindle's precision.
Tighten the bolt until the spindle body can not be turn by hand within the fixture.
Extreme tightening is not necessary or recommended.
Apply working force and check that the spindle is tight before using.
・Advice when using split type holders and all similer types installation methods
Insert a shim into the holder bore, and tighten the bolt with minimal torque.
Manufacture the holder with roundness and cylindrical tolerance of less than 5μm.
Insert a thin shim into the split in the holder and reduce the shim size in 5μm increments until
spindle is held firmly.
Tighten the clamping bolt to the torque specified for that size and type of bolt.
The final responsibility for ensuring product's stability for use in a given application is left to
the designer of the equipment in which NAKANISHI's spindle is installed.
NAKANISHI offers spindles with a wide variety of capabilities and specifications.
Please carefully check the product's specifications against the requirements of your
application and verify suitability and safety prior to initial use.
8. BREAK-IN PROCEDURE
Steps 1 2 3 4
Rotation Speed (min-1)5,000 10,000 20,000 30,000
Rotation Time (min)10 10 10 15
Items to Check
No Abnormal
Noises
Spindle Housing no hotter than 20ﾟC.
If hotter than 20ﾟC stop for at least 20
minutes, check installation and restart
Break-In procedure.
Spindle Housing
less than 20°C.
Table 1
During transportation, storage or installation the grease inside the bearings will settle. If the spindle is suddenly run
at high-speed excessive heat will cause bearing damage.
After installation, repair, initial operation, or long periods of non operation please follow the break-in procedure
detailed in Table 1.
Table. 2 Overhang and Speed
Overhang (mm) Max. Speed（min-1）
20 N x 0.5
25 N x 0.3
50 N x 0.1
※N=Max. Operating Speed with 13mm overhang. Fig. 10
9. CAUTIONS IN USING GRINDSTONES AND CUTTING TOOLS
①The proper surface speed for general grindstones is 600-1,800m/min.
②Do not exceed 13mm of overhang for mounted grindstones as shown in Fig. 10. If the overhang must
exceed 13mm, reduce the motor speed in accordance with table 2.
③Dress the grindstone prior to use.
④Do not use cutting tools with bent or broken shanks, cracks or excessive run-out.
⑤For grinding, the maximum depth of cut should not exceed 0.01mm radially or axially. Reciprocate the tool
several times after each pass to eliminate tool pressure.
⑥Always operate tools within the allowable recommended speed of the tools. Use of a tool outside of the
allowable speed of the tools could cause damage to the spindle and injury to the operator.
⑦Keep the tool shank and collet chuck clean. If contaminants are left in the collet chuck or chuck nut, excessive
run-out will cause damage to the tool and or spindle.
⑧Do not strike or disassemble the spindle.
⑨Please set the tools to minimize the overhang amount. 13mm is the maximum amount of overhang to maintain
high accuracy and safety.
10. TROUBLESHOOTING
13
If a problem or concern occurs, please check the following prior to consulting your dealer.
3.14 x Diameter (mm)x rotation speed (min-1)
1,000
Surface Speed (m/min) =
CAUTION
The maximum surface speed or rpm is always specified for a grindstone. Do not exceed the
maximum speed with reference to the calculating chart below. Always follow the grindstone
manufacturers recommendations.
Trouble Cause Inspection/Corrective Action
Spindle does not run.
The ball bearings are damaged. Replace the ball bearings.
(Return to NAKANISHI dealer service.)
Motor is broken. Replace the motor.
(Return to NAKANISHI dealer service.)
Overheating during
rotation.
Cutting debris has contaminated
the ball bearing, and the ball
bearings are damaged.
Replace the ball bearings.
(Return to NAKANISHI dealer service.)
Abnormal vibration or
noise during rotation.
Using bent tool. Replace the cutting tool.
Cutting debris has contaminated
the ball bearings. Replace the ball bearings.
(Return to NAKANISHI dealer service.)
The ball bearings are worn.
Tool slippage.
Collet chuck or chuck nut are not
correctly installed.
Check and clean the collet chuck and chuck nut.
And, tighten the collet chuck accurately again.
The collet chuck is worn. Replace the collet chuck.
High run-out.
The cutting tool is bent. Change the cutting tool.
Chuck nut is not correctly
installed.
Secure the collet chuck and the chuck nut
correctly.
The collet chuck is worn. Replace the collet chuck.
Inside of the spindle is worn. Replace the spindle shaft.
(Return to NAKANISHI dealer service.)
Contaminants inside the collet
chuck or the spindle.
Clean the collet chuck and the inside of the
spindle.
The ball bearings are worn. Replace the ball bearings.
(Return to NAKANISHI dealer service.)

Fig. 4
Cutting Tool
12
14
Chuck Nut
Spindle Shaft
Loosen
6. REPLACING THE COLLET CHUCK
① Remove the cutting tool according to the section 5 "CHANGING THE CUTTING TOOL" procedure above and
remove chuck nut assembly. (Fig. 4).
②The collet chuck and chuck nut are secured by a groove in the collet chuck and a flange in the chuck nut. To
remove the collet chuck hold the chuck nut in one hand and push diagonally down on the collet chuck. The
collet chuck should be released. (Fig. 5)
③Install the new collet chuck in the chuck nut by positioning the collet chuck in the chuck nut and pressing down
on a flat surface. (Fig. 5)
Fig. 5
Collet Chuck
Wrench Seat
Chuck Nut
Push
2014.11.20 005