Root 3 CNC - Test Pieces

A test piece was designed in Fusion 360 to do the initial testing and calibration on the machine.  It is a 10cm circle next to a 10cm square.  The circle has a center bore, and the square has a slot, with the two pieces connected with a small bridge.

The first test-run started well, but finished quite poorly, as the spindle went of course on the last run of the toolpath:



I thought maybe the feed rate was too high, so slowed it down and added a few more passes to the depth.  This actually made things worse:



The X-Axis belt was tightened.  While examining the machine after the 2nd run, it was noticed that the Y2 motor was not warm.  After investigation, a wire was found that had come loose, meaning the Y1 motor was pushing the entire spindle assembly from one side only.  The wire was tightened, and the test piece run two more times:







By the 4th print, things are looking a lot better (sure helps using both Y motors).  Measuring the X and Y dimensions, the test piece is off between 0.5 and 1.0mm.  This information will need to be included into the X+Y step calculations in order to get the CNC cutting more accurately.

Root 3 CNC - Base Threaded Inserts

In order to provide mount points for work pieces, brass M8 threaded inserts were purchased for installation on the base:



Using Microsoft Excel, a small gcode program was written to generate a grid pattern on the base, which was drilled with a 1/8" rotozip bit (endmills had not arrived yet):





These inserts required an 11mm hole, so using a metric bit and a 3-D Printed manual drill press, the pilot holes were expanded.  An impact driver using an installation bit was used to sink the inserts into the plywood:



Finally, a surrounding row of inserts was manually added outside of the milling area:



The base with most of the inserts installed:

Root 3 CNC - Spindle Ground

Not sure why, but Chinese spindle manufacturer's seem to not be interested in connecting tool ground wires:



I am accepting this deficiency for now, and will revisit the problem at a future date.  The top of the spindle will need to be removed, and tapped for a ground screw.  A grounding wire will then need to be added from the aviation plug to the grounding screw.

Root 3 CNC - Control Cable Strain Relief

In order to provide strain relief for the control cable, as well as stability for the water lines, a custom component was designed to mount to the top of the spindle.  The component is made from three 3D-Printed parts (files on Thingiverse):  a mounting ring, a tower, and the cable mounting block.



In order to provide a bit of extra strength, the tower has two bores which will accept 50mm M3 screws.  These were glued in to keep them from bouncing around during milling:





M3 screws connect the tower to the mounting ring:



M3 screws connect the mounting block to the tower:





The mounting block has two horizontal bores that will hold tie-zips.  After full assembly:

Control III Disinfectant Dilution

This concentrate is some nasty stuff.  Please read and understand the dangers of handling this liquid and take precautions as needed.  The specifications can be found here and FAQs can be found here.  That being said, if diluted properly, this is a strong disinfectant and can be used when other easier solutions are not available.



The diluted solution works through prolonged contact - basically spray it on and let it sit for 10 minutes, or soak something in a bucket.  Note that once you mix a batch, it is only good for 2 weeks before it needs to be disposed.  A 32 oz (946mL) bottle such as below is a good option.



Two snippets of the label directions are below: 

 


Depending on what you are doing, make a dilution that is up to 1 oz (29.5735mL) per 1 gallon (128oz) of water.

If you are measuring in metric, a little math is needed to get the proper amount for a 32 oz spray bottle:
= mL per ounce * ounces per container / mL per gallon
= 29.5735 * 946 / 3785.41
when you do the math without rounding, you get
= 7.39338 mL per 32 ounce spray bottle

Since I'm not operating in a hospital, I generally round down and use 3.5mL to 7mL per 32oz spray bottle, measured in a graduated cylinder...

Root 3 CNC - Preparing the Control Cable

The following cable is being used for the control cable:

Control cable Lapp ÖLFLEX 190 CY 4G1.5 16/4C (4x1.5/16 AWG) - 601604CY

In order to ready the wire for use, both ends must be prepared.  To prepare the GX16 end, the outer jacket and braid were removed:

then the conductors were soldered (dont forget to slide on heat shrink tubing before soldering):

A test fit shows that the connector fits well:

To complete the other end, first the outer jacket was removed, and the braid unwound.  A few bundles of braid were weaved together to form a wire:

If you have big hands, these tools are fantastic for getting into tight places like the braid disassembly:

4 Pc Stainless Steel Picks Probes Wax & Clay Sculpting Tools

A segment of the 16awg ground wire was soldered onto the braid:

and then covered in heat shrink tubing:

Finally the braid cable was marked with white electrical tape, and the end covered in heat shrink tubing:

The completed cable:

Root 3 CNC - Programming the HY02D211B VFD

Before connecting the spindle, the VFD has an initialization process to configure the device's firmware.  This apparently varies greatly per VFD, and in all instances seems to be documented poorly, so do your research and hope for the best.

The VFD/spindle bundle I purchased was from Amazon.  It contained a 110V VFD which upconverts to run a spindle at 220V (at least, I'm fairly sure thats what I bought).  The specific VFD model can be seen below (HY02D211B):

There was a video posted to Amazon which documented the settings required for this VFD as well as the process for programming:

• PD013 = 8 (factory reset)
• PD005 = 400 (max operating frequency)
• PD004 = 400 (base operating frequency)
• PD002 = 1 (set potentiometer control)
• PD070 = 1 (set analog input)
• PD072 = 400 (set high analog frequency)

This alternate video also describes the programming process well, but for a different model VFD (so the parameters do not match exactly).

In order to program the device, you must first connect the VFD to power without wiring the spindle (not sure the spindle not being there really matters, but I tried to follow the video steps).  This presented the first hurdle, as a complete wiring diagram was not included in the manual.  A little online research and a lucky guess provided the solution.  First remove the wiring access panels on the VFD:

Then run a 12/3 wire (in this case, 12/3 SJOOW) and connect as follows:

• Black (HOT) to R
• Neutral to T
• Ground to Ground

After reassembly and powering on the device, the programming can be completed using the following steps:

• PRGM (to start the programming sequence)

Then for each parameter, perform these steps:

• Up/Down arrows to select PD00x parameter
• SET
• Up/Down arrows to select value, SHIFT can be used to move the cursor
• SET (to accept the value)

Finally, to complete the programming, press:

• STOP (big red button to complete the programming sequence)

After completing this process, the next step is wiring the spindle to the VFD, to be covered in a future post...