Thread: Men's Shed Router

I think I have discovered why the Z limits don't work.

The Arduino CNC operating software loaded in the router is Grbl V0.9j.
Most of the documentation we have refers to V0.8, but with occasional reference to V0.9 without any warnings.
As detailed, the Z limit switches are wired into input D11.

Guess what: the usage of pins D11 and D12 were swapped with the revision to V0.9j.
Something to do with a pin needed for spindle control.

So, we can either re-arrange the wiring or go back to V0.8.
The problem with wiring changes is that, as suggested in the documentation, we have an intermediate daughter board (what a ridiculous term 'Shield' is), with filter capacitors on each of the digital inputs which will need re-arranging.
I think it easier to change to Grbl V0.8.

John

Haven't used Grbl but most controllers input pins are just assigned in software.

I think the use of D11 is determined by its connection to a specific pin on the Arduino, and this pin is the only one that can be programmed as a PWM output.
We have decided to do the D11/D12 swap, as it ensure compatibility with future Grbl revisions.
But we will postpone the work until we spread out into a larger box.

Today, the router received its first cutter and a couple of shed members went through a manual process, one line of Gcode at a time, to cut a simple letter in some thin MDF board.
I showed them that, for simple letters and numbers, this approach will suffice for the moment.
The search for suitable Gcodes, the reading and understanding of the lines of code, and entering progressively on the Command Line, were all very educational for those present.

New problems:
- the Z-axis height setting to be resolved,
- the Y-axis outboard traveller seems excessively tight on its track, possibly explaining some of the crabbing,
- the platen table is a bit out of level.

The first task next week will be to check the platen is flat, and the guide rails are at a constant height.
Squareness is something else to be checked.

John

Hi,

Mens Shed at Arncliffe NSW has just had donated a CNC 3020. It uses Mach3, and Lazycam was supplied free as that is no longer supported.

I'm looking here with great interest as we have all the usual setup problems. I am currently fiddling with text programming.

Cheers

Originally Posted by GeoffW1

Hi,

Mens Shed at Arncliffe NSW has just had donated a CNC 3020. It uses Mach3, and Lazycam was supplied free as that is no longer supported.

I'm looking here with great interest as we have all the usual setup problems. I am currently fiddling with text programming.

Lazycam is a bit less than "no longer supported". To quote from the Newfangled Solutions (Lazycam) website:

Due to the availability of other, more mature, low cost CAM packages, LazyCam development has ceased and it will remain in permanent Beta status... As the software is BETA, not all features are fully functional.

Rather than "fiddle" with Lazycam and text programing, perhaps invest your time in learning one of the packages that Newfangled Solutions recommend as an alternative to Lazycam.
Personally I'd pick a package compatible with Windows running in 64 bit mode. IIRC Windows 7 (64 bit) was introduced in 2010, so starting with packages that run on Windows in 64 bit mode should offer the best return on the operator learning curve.

The Z-axis height problem fixed by moving the head on the gantry and introducing a 25 mm sacrificial platen.
The tightness in the Y-axis movement was relieved and the two motors equalized for current resulting in much better movements.

The out-of-flatness is up to 1.5 mm, so a cut across the surface will have to be made.
If we use a 20 dia 2-flute carbide cutter with 6 mm shank to surface the MDF, can anyone advise suitable speed, cut and feed, keeping in mind the general flimsiness of this router ?
What sort of cut pattern would be recommended ?
How long would it take ?

Loaded a short text file to cut some letters and discovered the Gcode Universal Sender operates directly on the source file, so any program on a removable USB stick or CD/DVD should be transferred to the local Grbl folder before starting the cut.

There are now about 5 people very interested in the project, with some reviewing Gcode at home.

John

Originally Posted by ian

Lazycam is a bit less than "no longer supported". To quote from the Newfangled Solutions (Lazycam) website:

Due to the availability of other, more mature, low cost CAM packages, LazyCam development has ceased and it will remain in permanent Beta status... As the software is BETA, not all features are fully functional.

Rather than "fiddle" with Lazycam and text programing, perhaps invest your time in learning one of the packages that Newfangled Solutions recommend as an alternative to Lazycam.
Personally I'd pick a package compatible with Windows running in 64 bit mode. IIRC Windows 7 (64 bit) was introduced in 2010, so starting with packages that run on Windows in 64 bit mode should offer the best return on the operator learning curve.

Hi Ian,

Yep, saw that about LazyCam, and if we find it doesn't match our modest needs, we certainly will look around. Mens' Sheds are never wealthy though, and there is lots of competition for funds, so my assignment is to work with what was donated, for the time being anyway. I will not win friends by trying spend a bundle, so it will be freeware in the future, most likely. However not even Autocad products are ruled out by that !

The Mach3 machine controller seems pretty good for now, but it will not run on a 64-bit PC or on a laptop at all. Definitely that is archaic these days, and we may investigate Mach4 soon.

Just for now, softly softly catchee monkey. My main difficulty this week is trying to find a range of 1/8" shank engraving bits, ball-end and so forth. Dremel bits will fit I believe.

Cheers

Originally Posted by GeoffW1

Hi Ian,

Yep, saw that about LazyCam, and if we find it doesn't match our modest needs, we certainly will look around. Mens' Sheds are never wealthy though, and there is lots of competition for funds, so my assignment is to work with what was donated, for the time being anyway. I will not win friends by trying spend a bundle, so it will be freeware in the future, most likely. However not even Autocad products are ruled out by that !

The Mach3 machine controller seems pretty good for now, but it will not run on a 64-bit PC or on a laptop at all. Definitely that is archaic these days, and we may investigate Mach4 soon.

My main difficulty this week is trying to find a range of 1/8" shank engraving bits, ball-end and so forth. Dremel bits will fit I believe.

Yeh, I know that for Men's Sheds tool and technology is frequently a hand-me-down. Six years on would mean that Windows 7 (64 bit) is getting close to that status.

For 1/8" shank router bits are you aware of
1/8" Shank Carbide-Tipped Router Bits - Lee Valley Tools
Mini Downcut Spiral Bits - Lee Valley Tools

and other US based suppliers like
Dremel Type Cutters | Cutting Burs | High Speed Cutters | Router Bits

enjoy the learning

Have a look at Fusion360.

Don't waste your time with incomplete, unsupported, out of date software (LazyCAM)

Generally progress, just nothing much to show.

The guys decided to put a full size 25 mm platen on the router, so that meant time out selecting panels, cutting to size, routing out edges for biscuits, gluing, clamping to a 'flat' surface etc.

On the router we experimented with cut and feed with a 3 mm single flute cutter.
Much more than 1 mm in MDF at 12,000 RPM and 60 mm/min would over-heat the bit.
Seemed better at 180 mm/min.

While running a simple Gcode file, we hit 'Pause' to consider what to do about what appeared to be a bit of smoke.
The machine stopped as requested, but the only subsequent command available was to 'Resume'.
What we wanted to do was manually jog the cutter up a bit to reduce the cut - no way.
Had to close down the serial link communications from the laptop to the machine, then re-open to get manual control.

This is very odd to me, is it normal ?

One of the chaps came in with his Gcode 'homework' and we spent some time reviewing that, very satisfying to watch the CNC spark take hold.

We also reviewed the hundreds of lines of code generated by CamBam to surface the platen.
Quite intimidating with all its detailed absolute positional moves, and probably not required.

I will spend the week researching sub-routines and relative movements.
I am sure a hand-written program will be better for us.

John

Those feed rates are about 10% of what they should be. You will burn your bits. Look up some feeds and speeds.

You can't change the Z mid program.

Originally Posted by electrosteam

While running a simple Gcode file, we hit 'Pause' to consider what to do about what appeared to be a bit of smoke.
The machine stopped as requested, but the only subsequent command available was to 'Resume'.
What we wanted to do was manually jog the cutter up a bit to reduce the cut - no way.
Had to close down the serial link communications from the laptop to the machine, then re-open to get manual control.

This is very odd to me, is it normal ?

Hi John

From my perspective what you've described is as expected and totally normal.
The machine was executing a string of positional commands -- the G-code file.
Once execution had commenced, your control options should be limited to STOP (or ABORT), PAUSE and RESUME
any changes to the cutting or travel path, including changes to the cutting depth, would have to be represented by new lines of code that in turn might need compiling into the appropriate machine code.

Your machine should have a command equivalent to STOP or ABORT which should return the cutter head to the start (or tool change) position

Originally Posted by electrosteam

We also reviewed the hundreds of lines of code generated by CamBam to surface the platen.
Quite intimidating with all its detailed absolute positional moves, and probably not required.

I agree that hundreds of lines of code can be quite intimidating, however, I question your assessment that surfacing the platen is probably not required.
without surfacing the platen, how can you tell that it is parallel to the zero value for the Z axis of the cutter path?

Ian,
We do plan to surface the platen, just not use the bloated CamBam code.
I have done some research, there is no obvious looping construct in the Gcode for Grbl V0.9j, so a linear approach to the surfacing problem has to be adopted.

I think a few lines of relative position hand code in a text file, copied and pasted as many times as necessary to achieve coverage of the platen, is all that is required.

I am keen to push hand coding because I know quite complex jobs can be done this way, and most members of a Men's Shed are not going to ever achieve the ability to use CAD to draw, and CAM to generate code, with subsequent manual review.

As for the machine control, my memory is that the only option available was 'Resume', no 'Stop' or 'Abort'.
I will check this again next week.

John

I suspect a lot of people would be driven nuts by the hand coding - it can promote a much greater understanding of what the machine is doing and how its working, but as you move on to more complex projects it quickly becomes far less workable. What is simple for computer literate geeks will seem arcane and confronting to people just wanting to try out the new tool. Far better to be able to sit them at the computer, knock up a quick sign (very simple beginner project) and machine it out all in one session.

Check out cut2D as a good starting point for some very user friendly software that is an integrated cad/cam package and is reasonably priced. Alternatively, check out fusion 360, which also includes integrated CAM. I mention cut2d because there are some great video tutorials for getting people started, and the interface is so simple even my technophobic mother could use it.