This idea stems from attempts at cutting aluminum at more aggressive rates which often led to melted aluminum on an overheated bit. This coolant system allows for both increased feed/cut depths and prolonged cutting tool life. The design aimed to keep the mill portable by mounting all components to the mill itself and using an air pump instead of depending on an air compressor (with the pump running significantly quieter). Designed for the Sienci Mill One, it could easily be adapted for most compact CNC mills.
The design doesn't require any special skills beyond what would be needed to assemble the mill to begin with, and the ability to drill. Minus the pump and nozzle/regulator block, most of the materials used can be found at any local hardware store. Polycarb tube was chosen to see the level of coolant in the system, but this can just as easily be replaced with PVC pipe. It is highly recommend that the inside of the mill be coated with some form of sealant to protect the MDF walls from moisture.
2 - #8-32 x 1-1/4" Bolt and Nut
4 - #10-32 x 1-1/4" Bolt and Nut
4 - 1/4-20 x 1-1/2" Bolt and Nut
8 - 1/4" Flat Washer
- Drill and Bits: 5/32", 3/16", 1/4"
- Philips and Flat head screwdriver
- 7/16 Wrench
- Tube Cutter/Scissors
Step 1: Install Barbed Fitting on Regulator Block
The black block contains two regulator valves, one for air and one for oil. The valve for air (which has a larger diameter) must but replaced with the 90 degree barbed fitting to fit the 3/8" tubing from the pump.
First: Unscrew both regulator fittings by using a 7/16 wrench or pair of plyers on the nut located on top. Ensure the threaded holes are clear of debris.
Second: Install the barbed fitting by screwing it in by hand such that it is tight and facing away from the blue outlet hose.
Third: Re-install the oil inlet (smaller diameter fitting) by using a 7/16 wrench or pair of plyers on the nut located on top.
Step 2: Install Nozzle and Regulator Block to Gantry
First: Align the regulator block to the left side of the z-gantry such that a mark can be made for the location of the first hole.
NOTE: The bolts mounting the block will stick out the other side about a quarter of an inch, so ensure block placementis inset far enough that this will not interfere with movementof the gantry.
Second: Drill each hole using a 5/32" drill bit
NOTE: Avoid drilling both holes immediately. Mark and drill a single hole to use as a set point by placing a screw through the regulator block and the first drilled hole. The second hole can then be marked ensuring it aligns with the first and the block.
Third: Mount the regulator block using two #8-32 1-1/4" bolts and accompanying nuts
Step 3: Mount Air Pump
The pump is mounted through the rubber feet so they can act as a minor damper to the vibrations.
First: Mark the location of holes for the pump.
NOTE: Be mindful of the brackets on the inside corners of the CNC when marking holes for the pump
Second: Drill each of the four holes using a 3/16" bit
NOTE: Again, avoid drilling all holes immediately. Marking and drilling two at a time allows you to use them as set points to make sure the next to align properly. The rubber feet do give some leniency to alignment.
Third: Mount the pump using four #10-32 x 1-1/4" bolts and accompanyingnuts, layering a washer under the nut to protect the inside wall.
Step 4: Assembling Oil Chamber
First: Take the 2” polycarb pipe and cut it to approximately 15in. in length using a hacksaw.
Second: Removing the metal band, fit one of the rubber caps over one end of the pipe (roughly three quarters of an inch)
Third: Replace and tightenedthe restraining band such that the cap is held firmly in place
NOTE: The cap is intentionally undersized, thus too much force is not required. Be mindful to not overtighten and crack the polycarb pipe.
Fourth: Removing the metal band from the second rubber cap, drill a hole in the top using a 5/32" bit
Fifth: Feed the oil inlet line through the hole ensuring the check valve and filter stay on the inside of the cap
Step 5: Mounting Oil Chamber to Mill
First: Attach each bracket to the oil chamber and mark hole locations
NOTE: Again, be mindful of the brackets on the inside corners of the CNC when marking holes
Second: Drill each hole using a 1/4" bit
Third: Mount both brackets using four 1/4-20 X 1-1/2" bolts and accompanying nuts, layering a washer under the nut to protect the inside wall.
Step 6: Connecting Air and Oil Tubes
For the oil tube,
First: Pull through the oil tube through the top cap of the oil chamber, leaving enough for the filter to reach the bottom.
Second: Cut the tube at such a length that it will reach the regulator fitting
NOTE: Keep in mind the full range of motion of the mill. Move the gantry to the exact opposite end of the chamber and then measuring a length to the regulator to ensure enough slack is left in the tube.
Third: Attach the tube to the regulator by inserting into the push-to-connect fitting.
For the air tube,
First: Connect one end of the tube to the pump's barb fitting by pushing it on until it reaches the base of the fitting.
Second: Cut the tube at such a length that it will reach the regulator fitting'
NOTE: Again, keep in mind the full range of motion of the mill. Move the gantry to the exact opposite end of the pump and then measuring a length to the regulator to ensure enough slack is left in the tube.
Third: Attach the tube to the regulator by pushing it onto the barb fitting until it reaches the base of the fitting
Step 7: Normal Use and Operation
Based on the material being cut, oil can be regulated accordingly by tightening or loosening the screw on the fitting. For wood, oil is unnecessary and may be cut off leaving the air pump to clear out cuttings. For aluminum, oil can be regulated based on speed and depth of cut.