Basic cnc routers from China.

[Dave at Honley Tank]

In order to teach myself cnc, I purchased the smallest ("1610"), cheapest (about 170gbp) cnc router kit from Banggood. Not a good idea if you simply want a cnc machine!

Assembly without instructions or even an illustration, not even in Chinese, was achieved only due to many childhood hours with Mr Hornby's Meccano.

Long, cut short, I eventually located the required software to fire up the Arduino board but then had problems with something called gcode!

If you have the good sence to purchase a ready made cnc machine from GB company all that is done for you and you get plug and play cnc. I went through a massive learning curve and learned a lot that I don't need, in order to drive a cnc machine. That said, I'm still not cnc' ing because I cannot get the tool head to "home" to x/y zero I've had the tool correctly cut following my Cam drawing but only at some random position on the workpiece?

If we had to pay to watch You Tube I would now be bankrupt but I have been unsuccesful in finding what I want

So my hope in coming to rmweb is that some kind reader can kick me in the right direction.

I use Sketchup Make as CAD, Sketchucam as CAM and grblcontrol as the controller.Im sure that it is the latter that I am some how using incorrectly. Is any one here using that combination with success and can you help me?

I use Sketchup for 3d printing so wish to stay in that camp. l know of other control programs such as UGS and Mach 3 but why can't I get grblcontroller to work correctly?

Simply put, my question is how do I set up my machine to go to zero when I tell it to "go home" using my existing set up. It must be possible but how?

[DaveyH]

Dave

 

Before loading the G-code and running the job, you will need to zero the X, Y, and Z axis.

 

Have a look at this page which will explain how to do this on a cubic workpiece.

 

http://www.kronosrobotics.com/cube/

 

Good luck

 

Davey

[Dave at Honley Tank]

Dave

 

Before loading the G-code and running the job, you will need to zero the X, Y, and Z axis.

 

Have a look at this page which will explain how to do this on a cubic workpiece.

 

http://www.kronosrobotics.com/cube/

 

Good luck

 

Davey

 

 

Thanks Davey.

I had already done that  but the machine still cuts in some random area.

Assuming the tool stays within the workpiece area then it seems to cut exactly

to my drawing dimensions but with the drawings left hand bottom corner

becoming the workpiece top right hand corner.

I thought perhaps the stepper motors were somehow in reverse conection but

using the Grbl Controller's buttons every thing moves in the correct direction.

It seems to me that the grbl bumff fed to the Arduino at first fire up does not tell

the machine where its X/Y zero point is. Certainly I expected that prior to

starting a job, and after completing a job, the tool would park up at its natural

"home" over the drawing X/Y zero.

In summary, I think that the machine basic setup is in some way incorrect,

rather than the pre-job setup being done incorrectly.

Dave

 

 

 

 

 

 

 

 

 

[Al51]

Dave is this any help?

 

 

Al

 

[Dave at Honley Tank]

Dave is this any help?

 

https://www.youtube.com/watch?v=opJ4ZbKACTA

 

Al

Thanks for trying Al, but eveything up to the referal to " laser software" in that video I have done, but I dont understand that reference; certainly I got no "laser software".

That bit of the vidoe seems to be relating to the machine's settings and I'm fairly certain that that is where my problem lies; in the original gbl input to the Aduino board. It would help if I had any worthwhile understanding of programming, and indeed cnc'ing!

 

Perhaps my assumptions of what the machine should do are incorrect: I expectd "home" meant "take the tool head to x/y zero and take z to its upper limit"; I thought the gcode compiled by CAM from my CAD, related the machine's "home" to the work piece "home".

 

That's what I can't achieve; but are my assumptions correct?

[DaveyH]

Perhaps my assumptions of what the machine should do are incorrect: I expectd "home" meant "take the tool head to x/y zero and take z to its upper limit"; I thought the gcode compiled by CAM from my CAD, related the machine's "home" to the work piece "home".

That's what I can't achieve; but are my assumptions correct?

I am wary of teaching granny etc., but you have have configured GRBL to your cnc machine? When I cnc’d my Proxxon mill I had to invert some of the axis (axes?) to achieve machine homing in the location where I wanted it. The work coordinates system are different...

 

I found the configuration and faq pages of the GRBL depository on github really helpful. If you haven’t read these, I would recommend them.

 

https://github.com/grbl/grbl/wiki/Frequently-Asked-Questions

 

Davey

[flubrush]

Dave,

 

I think you might be falling foul of the way GRBL works.  I use it to drive my Emblaser 1 laser cutter and, basically,  I have to work to the 0,0 set by GRBL.  Here's a web page discussing it.

 

https://github.com/grbl/grbl/issues/257

 

I suspect you want to work as if using a controller like Mach3 where you can position your head then zero the counters and that becomes the home position for the job in hand.

 

Jim.

Edited November 24, 2018 by flubrush

[Dave at Honley Tank]

Dave,

 

I think you might be falling foul of the way GRBL works.  I use it to drive my Emblaser 1 laser cutter and, basically,  I have to work to the 0,0 set by GRBL.  Here's a web page discussing it.

 

https://github.com/grbl/grbl/issues/257

 

I suspect you want to work as if using a controller like Mach3 where you can position your head then zero the counters and that becomes the home position for the job in hand.

 

Jim.

Yes Jim, you've got that right.That's what I want but had not considered that Grbl would not allow it.

I'll have a look at other controllers, might even pay for one!

[Dave at Honley Tank]

I am wary of teaching granny etc., but you have have configured GRBL to your cnc machine? When I cnc’d my Proxxon mill I had to invert some of the axis (axes?) to achieve machine homing in the location where I wanted it. The work coordinates system are different...

I found the configuration and faq pages of the GRBL depository on github really helpful. If you haven’t read these, I would recommend them.https://github.com/grbl/grbl/wiki/Frequently-Asked-Questions

Davey

Thanks Davey; I have been trying to get to grips with the info on github for about 6 hours a day over the last few days, I'm pretty well brain dreary but getting there. However I think perhaps Grbl will not give me what I want.

When I started this thread I thought I had configured the machine but I have since found some errors which are now corrected.

Strange that you have cnc'd a Proxon because thinking I may do mine was part of the reason for buying this cheepo T8 as a learning cnc journey. Perhaps I'm getting too old to learn!

[Dave at Honley Tank]

Dave,

 

I think you might be falling foul of the way GRBL works.  I use it to drive my Emblaser 1 laser cutter and, basically,  I have to work to the 0,0 set by GRBL.  Here's a web page discussing it.

 

https://github.com/grbl/grbl/issues/257

 

I suspect you want to work as if using a controller like Mach3 where you can position your head then zero the counters and that becomes the home position for the job in hand

 

Jim.

Jim,

I've now gone through the "grbl issues" pages you quoted. This makes me think that my meager knowledge of programming is perhaps behind my problems with grbl controller.

Mach 3 sounds more user friendly and I ' ve seen frequent referrance to it.

Are you aware of any problems in using Mach 3 with one of these cheepo things?

Am I correct in thinking that the trial version can be used indefinitly and that even though 'watered down', this version is ok for us modellers?

Thanks for any further guidance

Dave

[flubrush]

I've now gone through the "grbl issues" pages you quoted. This makes me think that my meager knowledge of programming is perhaps behind my problems with grbl controller.

Mach 3 sounds more user friendly and I ' ve seen frequent referrance to it.

Are you aware of any problems in using Mach 3 with one of these cheepo things?

Am I correct in thinking that the trial version can be used indefinitly and that even though 'watered down', this version is ok for us modellers?

 

 

Dave,

 

First,  the problem with considering Mach3 is that it is really very obsolete.  It was designed to run on an older Windows 32 bit system and it interfaces with the CNC machine via the old parallel port.  It is well nigh impossible to get a suitable PC these days unless you go to the secondhand re-sellers who might just have something suitable.    My system is still running on a secondhand Dell 32bit running WinXP but I am considering getting a POkeys box which will replace the parallel port interface so that I could run it on more modern machines.  But on a recent Win 10 update,  Mach3 stopped working and someone did a bit of quick hacking on one of the versions to get round the problem - I run it on my Win10 PC just to check out GCode before going anywhere near the CNC setup.    So I would find it difficult to recommend Mach3 since it could get you into further messes in trying to set up an obsolete system.  The restriction on the free version is the number of lines it will run,  which I think is 500.  That seems a lot of lines until you run into a job with a lot of intricate moves.   It might be worth joining a forum like MYCNCUK - http://www.mycncuk.com/index.php - where there are a lot of people who are building their own systems and who might be able to suggest inexpensive solutions to your problem.

 

As for GRBL,  when using it with my Emblaser 1 I reckon that the controller knows the envelope of your setup and the only physical link between the GRBL controller and the machinery are the two micro switches which it uses to establish the machine home in the top right corner.   The operating zero is diagonally opposite.  I found that I had to establish a holder which set the corner of my material to 0,0 so that I could relate the laser head to the material with some accuracy.   I'm not sure how I could use GRBL with a CNC setup where setting up coordinates by touching off to the workpiece is the norm.  I'm sure we are not the first people to have run into this problem and I would suspect that a good hunt round the Internet with Google might well find similar matters being raised and possibly generate  some answers as well. :-)    I might have a look around later on but I'm up to my eyes at the moment trying to get my head round another 3D CAD program before a 3D printer lands on my doorstep. :-)

 

Jim.

Edited November 27, 2018 by flubrush

[flubrush]

David,

 

Just found this entry coming top of the pile in a search for "grbl setting different working 0,0"

 

https://github.com/grbl/grbl/issues/257

 

and there seemed to be a lot more in a similar vein which I haven't dug into yet. :-)

 

Jim.

Edited November 27, 2018 by flubrush

[Dave at Honley Tank]

David,

 

Just found this entry coming top of the pile in a search for "grbl setting different working 0,0"

 

https://github.com/grbl/grbl/issues/257

 

and there seemed to be a lot more in a similar vein which I haven't dug into yet. :-)

 

Jim.

Thanks again Jim?

I've got a goodish bit forward since I started this thread, thanks to yourself and others who joined in.

However I'm working at Manchester M R exhibition this coming weekend (demo stand) and I now need to prep for that so the cnc is going on the backburner for a few days at least, but I may have a rest from it for this year and come back fresh in January.

Have a good xmas evry body

 

Dave