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Type GRN-NC Tap Holders

Application Range

The tapping attachments of this type are mainly used on CNC controlled machines and are available in 4 sizes. Note: The tapping attachments of type GRN-NC are only suitable for cutting right-hand threads.

Specifications

Owing to the integrated reversing gear mechanism, the change of the turning direction of the machine spindle when reversing is eliminated. The resulting advantages are as follows:

• Saving time by shorter cycle times (see illustration).
• Less strain on machine by eliminating spindle reversal.
• Saving of energy by almost constant spindle speed.

Time needed when thread cutting with different tap holders

a = Time for cutting operation
b = Time for reverse of the tap
c = Acceleration-/De-Acceleration-Time between cutting stroke, and reverse stroke of the tap
t = f(n, Control)

Further equipment characteristics are:

• Suitable for revolutions up to max. 6000 rpm.
• Suitable for coolant pressures up to 700 psi.
• The transmission relation between running and reversing is 1 : 0.946, guaranteeing 100% drive.

• Safe locking of the tap via steel collets with high concentric accuracy.
• Installed damping elements compensate the arising reversing forces and guarantee a maximum tool life.
• Interchangeability of the shanks by adaption acc. to DIN 1835 B+E.
• Construction of the stop fixture acc. to a unit assembly system.

Collet Adaption

For adapting taps, the following collets are available:

Type ER = Collets without square drive hole.
Type ER/GB (Standard) = Collets with square drive hole.
Type ER/GB (for IKZ taps) = Collets with square drive hole plus clamping nut plus sealing disc.

The stop fixture has to be adapted to the machine. Please see questionnaire on page 247.

Service:
EMUGE offers a repair service for wear parts. This includes overhaul, checking of all the tap holder functions and includes the full, as new, guarantee on the function of the system.

Example of a Thread Cutting Cycle:

1. The tapping attachment is installed in the machine spindle by using a tool changer, the stop-arm engages in the stop-block fixture, releasing the attachment for normal operation.
2. The start position is reached via the quick feed. The safety distance x has to be checked.
3. The working cycle is carried out. Here the following points are to be watched:
   
   • The turning direction of the machine spindle may not be changed (this is executed via the turning gear mechanism in the attachment).
   • The programmed feed corresponds to 98-100% to the tap pitch.
   • There is no dwell time necessary.
4. The machine spindle is in start position.

Example of the movement z to be programmed:

* = depends on the rpm and must be adjusted, if necessary.
z = Movement
y = Chamfer length
x = Safety distance
t = Thread depth to be cut
G = Notching distance

Note: Safety distance = min. 0.5512 inch (14 mm).

Sequence

Ordering Information

1. Order GRN-NC housing based on tap capacity tap sizes No. 8 to 1/2 for GRN-NC 20 & 5/16 to 13/16 for GRNC-NC 32.
2. Order stop arm 65 mm, 80 mm, Fadal or Haas stop arm, bolts to side of GRN/NC with 4 socket head cap screws screws included with stop arm. (DIN. STD 65 mm with 40 taper and 80 mm with 50 taper).
3. Order CAT/BT V-Flange.
4. Order ER/GB square drive collets from page 296 and 297.
5. Order coolant seal disc if required.

Notes/Advantages

Coolant seal disc nut with GRN/NC/HD (HI-Q/ERC).

35/37 gear ratio for ease of programming now inclusive to EMUGE.

Aluminum applications reduce max rpm by 10% to increase life of unit; steel / cast iron reduce max rpm by 20%.

GRN/NC are to be applied on CNC machines in low to mid volume production applications. For high volume / high production we would apply the Switch-Master.

EMUGE Full Speed taps not recommended in GRN/NC units. Run with conventional tap feeds and speeds.

Expected life of unit between 50,000 and 100,000 cycles before servicing units. Can be repaired / serviced at EMUGE Northborough, MA. Facilities for a flat free.

For non-coolant thru the spindle applications coolant tube should be removed. You can also order a non coolant GRN/NC unit at approx less $300.00 US list price off GRN/NC20/HD housing. Delivery would be 3 to 4 weeks.

Programming

1. Use G85 bore cycle or G01 only.
2. Feed rate at 95% only in and out.
3. Depth of hole - self feed (.150) tap one hole and check for depth. Add to controller the additional distance required in Z axis to obtain correct depth of hole.
4. Clearance plane 10 mm (.400).
5. Disable spindle and feed override M49 to disable and M48 to turn back on.
6. Note: Fadal only you will also need to cancel accel/decel feed ramps (cancel G8) G9 to re-activate.

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