Finally got my proLIGHT CNC Mill running with UCCNC control software.

Chose that over mach3/4 because uccnc software seemed better made. Unfortunately, it too has bugs.

Most importantly, executing gcode.
Instead of running all codes in a block simultaneously, it does them in the incorrect order.

For example, code like

Instead of going to X0 Y0 defined in offset #54, it will go to coordinates of offset #55!
Only after executing that line, the offset will change to G55.
Similar issue with

Don't need to tell you this may lead to crashes.
So I changed the MasterCAM's post processor to output some of the codes in different lines.

Hopefully, devs will fix this issue soon.

In other news, I have just finished the first 2-tool piece.

It was a miniature skull figure made out of aluminum:

I got 150 bucks for machining that for a guy I met in a Facebook group. Nice!

The smallest endmill was 1mm ball nose, and it held up perfectly at max RPM of 5000 and feed rate of about 25ipm.

The DOC and stepover were about 0.004"

Now I wish it had a 20k spindle. If I could run at 100ipm, it would make a quick work of that little piece.
This way, it took 1 hour, which is not too bad either.

Cheers! 

After almost one month of waiting for parts, tracing wires, testing, soldering, and assembling. Here is the finished product!

Milling case hardened t-slot nuts:

Quick Tool change action with Tormach TTS holders:

Having done all the motor tuning and testing on the table, it was time to mount everything inside the machine enclosure.

I cut the heatsink to size enough to house four drivers, laid out some mounting holes, and drilled and tapped them M3.
Then drilled clearance holes in both the heatsink and the board and joined them with some 19mm long brass standoffs.

Drilled a hole in the enclosure for the motion controller mounting and LAN cable connection.

Then the main board containing drives and the power board and the breakout board were installed in the machine.
At this point, I realized the drive mounting scheme I chose was a mistake because it was a lot more challenging to connect the wires to the drive terminals so deep and so close to the enclosure. It helped to unscrew the main board, pull it out a little, connect the wires and only then push it back in and screw it to the wall of the enclosure.

Traced all the black cable going to the fuses and found which ones control the spindle and which ones go to the appliance plugs.
By fiddling with the controls on the front of the machine, identified all the wires and their functionality.

The Gecko G320X drives use the same (ERR/RES) pin controlling the drive fault reset and the error status.
When the drive is at fault (every time you startup or when the motor loses too many counts), it has a ground voltage of 0. If you pass +5v, it will reset the fault and enable the drive.

So I had to re-use the red cycle stop button to pul it to +5V when the machine is started. To sense the drive fault and stop the machine I used pin 12 (pull-down) on the C11G BOB. So when any of the drives pull ERR/RES to ground, the C11G board and mach4 react to it like an E-STOP.

The motors mounted back, and the encoder wires soldered directly to the data cable wires of the same colors. For that, I cut off the bulky DB-25 connectors.

Pay attention to the property belt tensioning. According to the manufacturer, the belt should sag a maximum of 1mm under the pressure of about 3 pounds applied at its middle point.

With everything connected, it is time to test the machine. See how it homes and runs!

I have been hunting for a very rigid but small machine for the last year or so.

And when I finally found one for sale on an auction in Minnesota, I could not pass.

Now the machine is in my garage.

It is a surprisingly heavy machine with a solid epoxy granite frame.

The features are as follows:

• 1.5HP 5000 RPM spindle
• Closed loop servos on all axes
• Power draw bar and a rack tool changer assembly

I built a table with casters for it and upon plugging it to a computer it turned out that.... It's dead!

The proprietary Animatics control in the back is not working, which means 95% of all electronics in the back must be replaced.

I was actually almost hoping for that because the original software is DOS-only. It is hardly convenient to work with it.

I want it to work under mach or LinuxCNC

So I ordered the required parts online and when all of them are here, I will start the retrofit process.

I will be documenting my process in comments.

Wish me luck!

HSMAdvisor/FSWizard got featured on DIY Engineering!

It seems like HSMAdvisor's machine profile settings and power compensation work just fine even for as small of a CNC machines as  Nomad  Carbide 3D:

Often times CNC programming tutorials only teach you how to create the tool-paths and not enough attention is paid on showing how to properly hold parts being machined.

At the same time efficient workholding is an art in it self and mastering it could drastically improve shop productivity and accuracy.

Without further ado let's jump into the workflow.

Step 1. Analyze the Drawing and the Model

We would have to look at the drawing, tolerances and the CAD model to develop the machining strategy.

This particular part has tight (+/- 0.001) tolerances between the features located on the top and the bottom sides. In addition to that it has a 2.5 degree draft angle on external walls.

Thus I decided to not use the soft jaws approach and machine it in a fixture. Soft jaws are generally OK for tolerances down to +/-0.001" but because of the draft angle the part would always want to pop out of the jaws.

Read More 

On the heels of the previous post.

YouTuber Breaking Taps has just published another of his interesting videos:

In it he is testing various High-Speed Machining techniques on his benchtop CNC router.

Also it is mentioned that HSMAdvisor does not seem to like those small high-feed cutters: at some point some calculated values become negative.

This is a legitimate criticism and it actually happens because default cutting depth of 0.024" becomes too large for the 0.24" Lakeshore high feed and mill and an actual Flute length of 0.015" must be entered in order to get proper values:

With actual 0.015" flute length entered the recommended speed and feed values are now in the safe end of the ballpark suggested by the manufacturer.

Task added to the issue tracker!

Just found a very good video of testing a table-top gantry router cutting mild steel.

YouTuber named "Breaking Taps" used speeds and feeds generated by HSMAdvisor to get a starting point.

To see where exactly he was in the calculations I decided to reproduce all of cuts in HSMAdvisor.

A couple of assumptions i made:

1. Tool Type: Solid End Mill. It is not recommended to use the HP/Roughing tool type on such light machines, so i assumed this is the tool BT used.
2. Tool Stick-out looked like about 3/4" so I used that number.
3. Material was set to A36 Hot rolled steel.

Test 1) Minute 4:52

Good, slow and very safe starting point.

Test 2) Minute 6:20

Twice as aggressive as before, but we can still push it further.

Test 3) Minute 7:10

Here we can see the lack of machine rigidity starting to show. But at 65% feed rate it is still alive.

Test 4) Minute 8:30

This last test did not go well at all.

The machine has finally hit its limit and the endmill broke at all S&F overrides at about 100%

Was this fault of the software? Not really!

If that were a heavier machine, the last cut would not even be considered that difficult.

Here is a full slotting cut on a Matsuura VMC:

And here is the calculation that was done using HP/Roughing End Mill tool type:

If i were using the "Solid End Mill" tool definition, i would have to dial the feed override to 176% to match the 45ipm feed rate!

So what can users of light machines do in order to not break taps end mills?

First of all make sure the spindle torque curve is built and enabled in your machine profile settings.

The easiest solution is to de-rate the spindle. There is "Warning at" level in machine profile settings. Set that to 50% for starters and it should save you from exceeding the machine's capabilities.

Overall this was a great test of this little machine's capabilities and of the great help that software like HSMAdviasor can lend in discovering them.

Please head over to Breaking Taps YouTube account and subscribe.

I came across a very educational post on Practical Machinist.

The topic-starter used over-aggressive speeds and feeds for his tiny BT30-taper machine and the retention knob (a.k.a Pull Stud) snapped causing the holder to drop lower, disengage from drive lugs and mess up the spindle bore in the process.

Just in case you don't know. Retention Knob looks like this and is used to pull the tool holder in to the spindle bore, thus holding it in place:

(Retention knob is the detail on the right)

This whole article is to remind everyone the importance of proper tool holder and retention knob maintenance.

Retention Knob Tips

• Retention knobs (according to HAAS) have service life of about 6000-8000 hours.
  That means that if a tool holder is used 3 hours a day, you should replace the knob after 8 years in service.
  For smaller BT30 knobs, you should probably replace them every 4 years.
• Retention knobs should be lightly oiled or greased (if TSC is used) once a month to lubricate the draw bar.
• There should be no visible damage or rust on the knobs.
  
• Do not exceed the maximum cutting force recommended by your machine manufacturer.
  Some of those high-helix end mills create large down-force that could in certain cases cause the knob to snap!
• Also retention knobs should be torqued to manufacturer specs and the tightness should be regularly checked. Overtightened knobs may lead to taper of the tool deforming and causing uneven contact with the spindle bore.

Tool Holder Maintenance Tips

• Keep Tool Holders clean. Especially the taper part that is matching to the spindle bore.
  Wipe them with a clean cloth. 
• Do not use sand paper to clean tool holders! Soft Scotch-brite is acceptable to clean very dirty ones.
• Repair dings and notches on the taper.
  Even an aluminum chip will cause a ding, that will create a high spot around it.
• Replace worn-out tool holders with new ones.
  Signs of ageing is uneven contact with the spindle bore and fretting (blackening of taper in certain spots)
• It is also a good idea to re-grind the spindle as well when replacing the tool holders - there are lot's of services that do that for very reasonable price.
• Like wise when a new machine is purchased, only new holders and retention knobs should be used. Using old worn out holders on a new spindle bore will lead to its premature wear and even damage.

Those are all the things I could think of at the moment.
Let me know if there is anything missing.

Have a safe and productive week!

3D Prining is about to to take over traditional machining the same way CNC Machining took over manual machining.
Eventually 3D printing will replace casting too.

Since 3D Printing does not require complicated setup and programming, this in turn will lead to massive loss of machining-related jobs.

Read more to see if this is true!

Read More