Using the technology

[John Stevenson 1Participant @johnstevenson1]

After the recent threads [ and flames ] on CNC and CAD I thought I’d take interested parties thru an everyday job.

 

Pretty average brush ring out of a fork truck motor, shot from the back.

 

 

A bit unusual in that this one is broken, usually they are burnt out.

Now these pictures have literally just been taken and uploaded and the idea is to try to do this in real time. probably take a bit longer as regards taking pics, uploading etc but should give a good idea. Time at the moment is 23:13pm.

John S.

 

[John Stevenson 1Participant @johnstevenson1]

[Chris TriceParticipant @christrice43267]

You working a night shift John?

[John Stevenson 1Participant @johnstevenson1]

23:38

 

Drawing now done and saved as a DXF file.

 

Now onto programming this for the router to cut out of a sheet of Tufnol.

 

John S.

[John Stevenson 1Participant @johnstevenson1]

23.54

 

CAM drawing done, took a bit longer than it should as I had an update to the computer last week and on reinstall of the programs all the tool files were new so had to edit the tools.

 

Second line up from the bottom tells me that this is going to take 6 minutes 17 seconds when t gets nailed onto the router in the morning. all thats then left is to counterbore the fixing holes and transfer the brush boxes over.

A couple of years ago this job would have taken me about 3 to 4 hours. now it’s down to 41 minutes to get the file but it should have been less. At no point tonight have I seen the G code nor do I need to, I have a file called 27_6_11 brushring on a memory stick and that’s all I need.

Total time tomorrow should be 45 minutes tops and the truck will be back running by dinnertime easily.

John S.

[Tony JeffreeParticipant @tonyjeffree56510]

John –

 

Makes the point very nicely.

 

Another example of a 1-off that was done using CNC, and which would have been very time consuming indeed using manual techniques, involving a steep learning curve in hand-engraving just as a starter:

 

http://www.jeffree.co.uk/pages/Chapter-ring.html

 

Again, not a single line of G-code was written during this process. As observed in the text, I could have made a more traditional-looking job of the numerals; with a larger table available to me on the mill (or maybe a small CNC router), the answer would have been to draw out the numerals “properly” in CAD rather than using a rotary axis and the in-built Roman fonts.Also, the CAD/CAM tools available to me have much improved from the rather primitive SuperCam package I was using back then, so life is even simpler now.

 

A later example is this brass plaque that I engraved using a CAD drawing for the outline/screw holes and DeskCNC’s in-built stick fonts to engrave the text:

 

Again, doing the same by hand would have been impractical both in terms of time and personal ability.

 

One-off work is just as legitimate a target for CNC tools as is repetition work, and IMHO the former is much more likely to be useful in the average ME’s workshop.

Regards,

Tony

[EtheAv8rParticipant @etheav8r]

This is very interesting – how long would it take to learn to use the drawing package used to generate the dxf file, and is the CAM drawing from another program, or a result of the dxf file. And then what kit is required CNC Mill wise – and is it all very expensive?

 

I am interested in this, and the process and would like to understand a little more of just what is required to do this. I am about to buy a mill, am a complete beginner and know practically nothing! CNC for non programmers sound interesting – but I would want to be able to perform some manual milling/drilling too – is this requirement mutually exclusive on a low cost single mill setup?

[Jim NolanParticipant @jimnolan76764]

John,

Keep preaching you never know!

Given I have a history of bad luck when it comes to measuring hole centres the only thing I can possibly see that would take a bit of time was measuring up the original part.

On my own hobby machine Tormach offer a CNC scanning package and software to reverse engineer parts. They also have a demo video which really explains how you can get started for a relatively cheep outlay

http://www.tormach.com/videoselect.php?vid=0

 

Of possible interest this week I notice on the flyer from Liddle they are selling a USB microscope for about £20. Which looks exactly like the one in the video so it might be worth a punt just to see what it can produce.

Although i work from my own drawings and don’t get into the refurbish or repair world. This would still seem a handy arrow to add to the quiver.

Jim

[Tony JeffreeParticipant @tonyjeffree56510]

Posted by EtheAv8r on 28/06/2011 11:20:32:

This is very interesting – how long would it take to learn to use the drawing package used to generate the dxf file, and is the CAM drawing from another program, or a result of the dxf file. And then what kit is required CNC Mill wise – and is it all very expensive?

 

I am interested in this, and the process and would like to understand a little more of just what is required to do this. I am about to buy a mill, am a complete beginner and know practically nothing! CNC for non programmers sound interesting – but I would want to be able to perform some manual milling/drilling too – is this requirement mutually exclusive on a low cost single mill setup?

If you are reasonably familiar with PCs and Windows, getting the hang of a drawing package is fairly quick. Once you have the drawing in CAD, you save the drafing as a DXF, import that into the CAM package, where you select how it will treat the various parts of the drawing (for example, if you had drawn a circe, you might intend that to be a simple circular toolpath, or the outer edge of an “area clear” operation). The CAM program generates the Go-code, which you load into the CNC control that interprets the G-code and translates that into coordinated moves of the various axes.

 

Kit-wise, the expensive way is to buy a purpose-built CNC mill (for example, from Tormach, Taig, or Arc Eurotrade). The cheaper way is to start with a manual mill and convert it; Taig can sell you a “CNC-ready” mill that has the necessary motor mounts, to which you would add your own motors, drivers, etc. An example Taig conversion is documented here:

 

http://www.jeffree.co.uk/pages/taigcncpt1.htm

 

and here:

 

http://www.jeffree.co.uk/pages/taigcncpt2.htm

 

although these days I would probably use Mach 3 instead of Desk CNC, so the details of the electronics would change a bit.

 

There are ways of making the end result usable both manually and under CNC control. The simplest way is to use stepper motors that have double ended shafts, and transfer the hand crank to the back end of the motor. However, with Mach 3 there are several options for adding hand controls (so-called “pendant” controls) that give you manual control of the mill via the motor drive system.

 

Regards,

Tony

[blisterParticipant @blister]

Well done John, I am now seriously considering CNC. The only thing that worries me is losing the skills required for manual machining. Upon reflection this shouldn’t happen as at work my workshop has machines from the late 1800’s driven from overhead belting by a steam engine. During the day I demonstrate ‘old style machining practices’ so I could keep the skills alive that way and thoroughly enjoy CNC at home

I guess you are officially “Preaching to the converted”

Well done again.

Regards,

Phil

[Richard Willcox 1Participant @richardwillcox1]

My first post:

I am an experienced machinist, returning to it as a hobby. This is something I’m really interested in.It stimulates me as I’ll be learning a new skill. Thanks for posting the link

it’s one of the best demo’s I’ve seen in ages.

 

[John Stevenson 1Participant @johnstevenson1]

I don’t mind taking an example all the way though but in more detail if it will be appreciated.

 

What seems to be the area of most interest ?

 

John S.

[Steve GarnettParticipant @stevegarnett62550]

Just FYI, the images in this thread that John has posted don’t show up in Firefox. Tony’s one does, though. The only difference between them that I can ascertain is that whilst Tony’s is hosted by this site in Albums, John’s are external links to his own site.

 

Yes that seems ludicrous. Especially as if you view the page in Google Chrome, all the images work fine. And no, I can’t find any settings in Firefox at all that will alter this. Ho Hum…

[Anonymous]

Oeeer, I’m using Firefox and, as far as I can tell, all the images show up. I’m using version 3.6.18. I haven’t upgraded to release 4, as the upgrade process fell over. Doesn’t give you much confidence, if they can’t even get the upgrade software to work!

 

Regards,

 

Andrew

[Steve GarnettParticipant @stevegarnett62550]

Oh. I’m using release 5!

[Tony JeffreeParticipant @tonyjeffree56510]

Posted by Steve Garnett on 28/06/2011 22:05:45:
Oh. I’m using release 5!

I am also using FF #5 and all the images show up just fine…

 

Don’t you just love PC’s?

 

Regards,

Tony

[Les Jones 1Participant @lesjones1]

The pictures show up OK on both my PC’s. One 32 bit XP pro with Firefox 4.01 the other window 7 64 bit with Firefox 5.0

Les.

[dcostaParticipant @dcosta]

Hello Steve.

At my machine, with Firefox upgraded to version 5.0, I also can see the John’s images.

Regards,

Dias Costa

[Steve GarnettParticipant @stevegarnett62550]

Weird. It’s an absolutely default installation. I’ve just checked the error messages for this page, and the most interesting one (apart from all the word 2007 parsing errors) is the one that says:

 

Security Error: Content at http://googleads.g.doubleclick.net/ may not load data from http://www.model-engineer.co.uk/forums/postings.asp?th=52816.

 

But that of itself doesn’t explain why remote images won’t display… mystery continues.

[John Stevenson 1Participant @johnstevenson1]

Steve,

I think I know the answer.

 

From my records you have paid no rent this month to view my pictures.

Cough up or the boys will be round. <bg>

 

John S.

[Tony JeffreeParticipant @tonyjeffree56510]

Posted by John Stevenson on 28/06/2011 22:31:09:

Steve,

I think I know the answer.

 

From my records you have paid no rent this month to view my pictures.

Cough up or the boys will be round. <bg>

 

John S.

Not the boys that got “Santa’s Slaves” tattooed on their chests by a dyslexic tattooist, by any chance? <bg>

 

Regards,

Tony

[Steve GarnettParticipant @stevegarnett62550]

Posted by John Stevenson on 28/06/2011 22:31:09:

Steve,

I think I know the answer.

 

From my records you have paid no rent this month to view my pictures.

Cough up or the boys will be round. <bg>

 

Oh, is that what it is? Rent??? Perhaps I’ll just stick with rent-free Chrome!

 

And trying to send round Santa’s Slaves won’t do any good. I think you’ll find that there’s a Claus in their contracts that means they won’t work south of the Thames (or is it the Watford Gap?)

 

But it was worth looking at the pictures – good demo of CAD/CAM value.

 

Edited By Steve Garnett on 28/06/2011 22:50:52

[John Stevenson 1Participant @johnstevenson1]

Definitely Watford Gap.

 

Gotta go down sarf tomorrow to install a CNC, got me passport, change me money tomorrow but the Tom Tom needs a different country upgrade.

 

John S.

[EtheAv8rParticipant @etheav8r]

Jim

 

Your link was very enlightening – and very interesting.

 

Tony

 

Thank you for your reply…. you have whetted my appetite further and I am getting very interested in this technology. I am looking to buy a mill and all is on hold now, untill I can get more info/answers…… But rather that hijack this thread I will post a new thread.

 

John

 

You have started somethin here which I feel is going to end up costing me more than I bargained / budgetted for (which originally was a cheap mill).

Edited By EtheAv8r on 29/06/2011 13:02:21

[Tony JeffreeParticipant @tonyjeffree56510]

Posted by EtheAv8r on 29/06/2011 13:00:09:

Jim

 

Your link was very enlightening – and very interesting.

 

Tony

 

Thank you for your reply…. you have whetted my appetite further and I am getting very interested in this technology. I am looking to buy a mill and all is on hold now, untill I can get more info/answers…… But rather that hijack this thread I will post a new thread.

 

John

 

You have started somethin here which I feel is going to end up costing me more than I bargained / budgetted for (which originally was a cheap mill).

Edited By EtheAv8r on 29/06/2011 13:02:21

Sorry about that, John…

 

Regards,

Tony

[Author]

Posts