[Novakon]

We would like to take this opportunity to introduce the newest capabilities of the Torus and the NM-145 Spindle motor upgrade. We had posted this article on another location but decided to relocate it to its own thread. We hope you will take the time to become familiar with this newest capability.

The fundamental feature for these machines is the new spindle AC motor that provides rigid tapping capability. Our approach was to provide additional tapping capability along with a better performing spindle motor. The approach we took was to install an AC servo motor with a commercial driver. Both units are heavy duty and designed for industrial use. The advantages we find with this approach, is the ability to perform rigid tapping seamlessly.

For your information the specs of the AC synchronous motor are:

• 1200W power (1.6 HP)
• 0 - 3000 RPM (0 - 4500 with step up pulley)
• 10000 steps per revolution encoder resolution
• Accuracy to within +/- 1 Hz

The motor had to be externally mounted due to the limited space within the head casting. As such, we designed and built a new motor mount casting that will fit on the NM-145. We have tried to minimize the number of parts to the ones illustrated in the attachments below. The result is a nice package that can be mounted with a few drilled/tapped holes.

The electronic package had to be reviewed as well in order to address the new servo driver. A new electronic chassis has been built to mount the driver and host some of the components from the previous controller. The heart of the tapping capability is the product of a new break out board (BOB), designed by Novakon, that performs function switching. The two functions are continuous rotation of the spindle motor and discrete control of the rotation similar to a rotary table. This BOB switching capability was facilitated in order to eliminate the software changes that would be required within Mach3.

The function switching is automatic within the BOB. The only decision that has to be made by the customer is if a 4th axis rotary table will be used or not. There is a single mechanical switch on the BOB to select the tapping function. When selecting the tapping function, the rotary table has to be disabled since the control of the servo is now under output “A” control from MACH3. This trade off seemed to be a reasonable compromise. Of course, the rotary table is still available for use if tapping is not desired.

The G-code for tapping is very easy and straightforward. This is due to the BOB controlling the switch between the continuous rotation and discreet control. The sophistication between the commercial servo driver and in conjunction with our BOB has removed the complexity of programming via G-code. The programming of the driver/MACH3 steps per revolution is set to easily program the number of spindle revolutions from G-code. As an example, if an operator was to use a ¼-10 tap and thread the tool one inch into the material, it is simply done by writing:

G 91
A 10, Z-1
A-10, Z 1

This will do a helical cut one inch into the work piece and then reverse helical travel out.

“Pecking” can be done as well by a variation of this program. An example of the “pecking” is shown in the video Novakon - YouTube. Shown in this video clip, we are tapping ¼” Aluminum plate with a 5/16-18 tap. We chose a pecking operation to illustrate the precision of the rotation of the spindle. The soft Aluminum can be tapped without pecking, especially if a 2-flute tap is used instead of the 4-flute tap as shown in the video. More video projects are in progress showing tapping of harder metals such as steel and also softer materials like machinable wax demonstrating the precision and preservation of the threads.

The spindle motor upgrade KIT is a direct result of the research and work done creating the Torus line of milling machines currently available in our website. This KIT is available on a pre-order basis by contacting [email protected].

We hope this article has helped our followers to better understand the work we are doing to improve the performance and reliability of our equipment.

Best regards,

The Novakon Team