David A's Benchtop CNC Version 2

[davida1234]

Final step for completion of the basic machine hardware assembly:
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INSTALLATION OF LINEAR DRIVES:
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The machine uses rotating ball nuts:



Some specs for the drives:

• Size: 12mm ball screw
• Lead: 0.1575" per ball nut revolution
• Suggested max RPM: 3,000
• Max speed @ 3,000 RPM: 470 IPM
• Rotational mass: 4.4 ounces (without bearings)
• Rotational mass diameter: 1.1"
• Belt reduction ratio: From 1:2 to 2:1
• Reduction on the machine: 1:1 on X and Y axis. 1:1.25 on Z axis.
• Motor size: NEMA 23
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[peteeng]

Hi David - You got me excited there I thought you had "real" linear drives but then I looked them up and they are called linear motors...

https://www.hiwin.us/products/linear-motors/

Keep at it, Peter

[davida1234]

Hey Peter,

I don't know what you want to call them. I guess every power source driven actuation is a "drive" and every single axis actuation is a "linear drive"?

I would probably call a linear drive with all necessary gears, belts and supporting parts "drive line".

[davida1234]

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INSTALLATION OF Z-AXIS DRIVE:

Remove the bridge on the Z-slide shafts:



The drive will be installed on those four standoffs:



Linear drive in place:

[davida1234]

With the motor installed:



Place the bridge over the ball screw and the shafts:



Z-axis linear drive installed:

[mactec54]

Hey Peter,

I don't know what you want to call them. I guess every power source driven actuation is a "drive" and every single axis actuation is a "linear drive"?

I would probably call a linear drive with all necessary gears, belts and supporting parts "drive line".

What you have is a Ballscrew with a rotating nut, it still a Ballscrew with a driven Ballnut, it is not a linear drive

[davida1234]

Thank you for the clarification, mactec.

I would correct the header to "ball screw installation" above but the "edit" button is no longer there.

[mactec54]

Thank you for the clarification, mactec.

I would correct the header to "ball screw installation" above but the "edit" button is no longer there.

It does not really matter how it is called as it is still linear motion using a Ballscrew

[davida1234]

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INSTALLATION OF Y-AXIS BALL SCREW DRIVE:
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Turn the ball screw all the way down so that the one end sticks out just about an 1/8" at the ball nut cage:



Thread the other end of the ball screw through the eye of the big front brace:



All the way through at the other end, place the motor mount/ball nut cage between the gantry braces:



Motor mount/ball nut cage in place:

[davida1234]

With the motor mount in place, turn the ball screw all the way in towards the back
until it sticks out about an inch over the back cap and clears the eye at the front cap:







Install the grommet into the eye of the front brace.
Make sure it is seated all the way around:



Back out the ball screw until it goes through the grommet and clears it by about 1/8":

[davida1234]

For particularly dusty environments, you can place two brush stubs at the front
and rear of the carriage. They help to clear dust on the non-rotating ball screw:



Place and screw down the dust covers front and rear on the carriage:



Screw down the motor mount/ball nut cage with four screws:



Make sure the rear of the ball screw is placed into the back cap seat:



Place the clamp onto the screw and tighten down:

[davida1234]

Motor in place:



Wiring attached:



Installation of Y-axis ball screw/rotating ball nut is completed.
Repeat on the A-axis:

[davida1234]

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INSTALLATION OF X-AXIS BALL SCREW:
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Install a hex cap screw on the motor plate as shown, leaving
a clearance of about 1/4" between the hex cap and the plate:



Push the hex cap/motor plate through the hole and slide to the right:



Once motor plate/ball nut is placed, install the two bottom screws and start
tightening while making sure that the ball screw is centered with the grommet eye:





Two bottom screws tightened down:



Tighten the hex cap screw behind the cross brace:



Install and tighten the support brace onto the motor plate:

[davida1234]

As with the other grommet eyes, back out the ball screw to clear the grommet
eye, install the grommet and turn in the ball screw through the grommet:





Place the other end of the ball screw onto the clamp pillow:



Place the clamp on the ball screw and tighten down:

[davida1234]

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The installation of ball screws and the mechanical assembly of the machine is finished.
This will be posted on the website as the base machine on which I am working right now.

Next up will be all peripheral additions.

Image of all ball screw arrangements (some drag chains omitted for clarity):

[davida1234]

Mechanically finished machine from the front:

[davida1234]

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The machine is mechanically finished and ready to accept all your electrics, electronics and peripherals.

I also designed expansion sets like spindle cooling, cutting fluid or air, dust collection,
vacuum holding, wiring, etc. which were specifically made for this machine.

The following posts will show the installation of all the expansion sets.

SPINDLE COOLING EXPANSION SET

Spindle cooling set contains two 8-pipe radiators and fans,
a 200 mL reservoir, a brushless mag-drive, 60 gph pump and hardware.

This setup has been running for two years on my prototype machine without any problems.

Parts for water cooled spindle set:



Set will be mounted on the top plate of the X-carriage:



Install one side with two screws as shown:



Looking from the inside:

[davida1234]

Install the second radiator/fan the same way on the other side:



Install the reservoir bracket and the two standoffs:



Place the reservoir on the standoffs and secure with a zip tie to the bracket:



Slightly warm up the ends of the 1/4" hose to soften and connect the parts as shown.
It is a bit tight but the hose will go over the nipples.
On the prototype machine, it didn't need any clamps to stay on:



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THIS CONCLUDES THE INSTALLATION OF THE SPINDLE COOLANT SET.

[davida1234]

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WIRING EXPANSION SET:
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Wiring set includes one junction box, three PNP sensors and all necessary signal and power wiring for
4 servos, the sensors and associated connection wires connecting the machine to your controller.

The Molex connector ends work with Teknic servos or the ends can be modified to fit other motors.

Included OMKQN sensors do not require magnets and have been working good on the prototype machine.
I could not measure any differences between them and the higher end sensors.

[davida1234]

Junction box will be installed on the back brace using these holes:



J-box installed with the spacers.
On top is a saddle for the reservoir to sit on:



X-axis limit sensor will be installed onto the slot of the back brace: