Messages

251

Show"N"Tell ( What you have made with your CNC machine.) / Re: Engraving

« on: July 24, 2013, 06:31:03 PM »

I think you could do it with a spring loaded engraving cutter holder and a diamond burr. The spring loaded cutter holder gives you a constant tool pressure when engraving delicate or brittle materials reducing the chance of fracture.
There are some posts elsewhere on the forum regarding converting images to G-Code, I've not done this yet myself,
Regards,
Nick
 

252

G-Code, CAD, and CAM discussions / Re: BobCAD-CAM Bore depth, limited to 2" ?

« on: July 24, 2013, 05:34:17 PM »

Can you define your Tool Holder/Arbour combination to effectively extend the length of the tool and still give appropriate holder/arbour geometry at the top?
I know it's a common workaround when using T-Slot cutters to undercut to define them as a disc cutter on a long holder,
Regards,
Nick

Edit -  I've just defined a 1/2" tool with 1/2" holder and 1/2" arbour with overall length of 5" so this looks like a possible workaround ;-)

253

Show"N"Tell ( Your Machines) / Re: Improving a cheap 4th axis

« on: July 21, 2013, 08:41:01 AM »

Here it is finally mounted on the mill -



After a false start with a Chinese 5-Axis board which promised the world and delivered only 3 working outputs I took a look in my existing 3-Axis Routout CNC box, imagine my surprise when I found 3 separate axis control boards and a full breakout board 
By moving the mounts for the 3 vertically stacked Routout CNC axis boards I made space for an additional single axis board. A USB lead collects the required 5v logic supply for the new board from my PC and a connector from Maplin on the back gives my 4th axis output.
While I was in there I replaced the 4-pin inputs connector with a 6-pin connector making all 5 inputs available, then replaced the original home switch wiring and junction box which included a bench level connector for the 4th Axis and an Emergency Stop button.
Isn't alibrating a rotary axis is a wheeze? Get it looking good with 1 turn then try 5, 5 turns then try 10, 10 turns then try 20, 20 turns then try 50, can I stop now? 

 - Nick

254

Show"N"Tell ( Your Machines) / Re: Improving a cheap 4th axis

« on: July 07, 2013, 04:37:08 PM »

Cheers Brett!
I'll definitely look at tying the brace to the plate, that's a great idea,
Many Thanks,
Nick

255

Show"N"Tell ( Your Machines) / Improving a cheap 4th axis

« on: July 07, 2013, 10:12:02 AM »

I bought a cheap 4th axis and found that the backplate and stepper shaft can flex slightly under load.
By adding a couple of bearings on plugs with a bar bridging them the majority of load is now taken by the bar under compression -



The cap in the stepper end is an eccentric adjuster allowing precise adjustment of bearing spacing.

I'd welcome input as to whether a tensioner a good idea now that belt tension no longer applies significant bending moment to the stepper shaft or axis back plate?

 - Nick

256

G-Code, CAD, and CAM discussions / Re: All Dressed Up & No-Where To Go?

« on: May 19, 2013, 03:22:39 PM »

I'd like to thank Tweakie, plus all those who replied via PM for some brilliant assistance and advice, with no prior experience I needed to get up and running, with the assistance provided I narrowed down the options and bought Bob-Cad/Cam, the Video Professor DVDs which came (very quickly for USA to UK shipping!) with the software are proving a boon to a complete novice,
Regards & Thanks,
Nick

257

G-Code, CAD, and CAM discussions / Re: How do you get to g code using cad /cam?

« on: May 10, 2013, 12:32:25 PM »

Hi Buzz,
I was recommended GSimple ( http://www.gsimple.eu/ ) as a free starter package by a kind member of the mod team here, playing around with it for a week prepared me sufficiently that when I purchased a commercial Cad/Cam package I was able to produce working 2D engraving code on the same day as installing.
Something that slowed me down initially was tool and tool holder definition and selection, once I installed BobCad/Cam I knew the first thing I should do is define my tool holders, arbors and tools in the tool library,
Let us know how you get on,
Nick

258

Feature Requests / SNMP Status

« on: May 08, 2013, 07:06:32 AM »

That's it really, this would allow the use of any network connected device with SNMP monitoring software to poll the status of the machine, as little as once a minute would be fine, and sound an alarm in the event of an error or job completion,
Simples ;-)
ATB,
Nick

259

G-Code, CAD, and CAM discussions / Re: BobCad/Cam setting incorrect measurement units in Gcode

« on: May 08, 2013, 04:25:36 AM »

It seems it's hard coded in the Post rather than passed across from CAM to Code, I can live with editing one character until I find which bit of the post to edit to make a permanent change,
I'll get there,
Nick

260

Show"N"Tell ( Your Machines) / My Benchtop Mill

« on: May 06, 2013, 03:24:57 PM »

This is my benchtop mill -



I bought it with known stepping problems at higher motor speeds and swapped out the motor & drive to resolve the problems, the new motor & drive give me 0 - 6000 rpm adding a spare PC, monitor and peripherals got me up and running with Mach3.
Some keypad controlled surfacing cuts confirmed it would do what milling I needed.

Todays project was to fit the mysterious spare engraving spindle that came with my Gravograph pantograph engraving machine, drive it from a custom made pulley on the mill spindle and give it some sprung Z freedom whilst keeping X & Y nice & rigid.
This is what I came up with - 



Using a custom bracket mounted on a micrometer ball slide it allows drag and cut engraving of existing uneven and curved surfaces and gives me 0 - 28000 rpm, the ball slide now resides at end of travel held by a coil spring, with the micrometer providing pre-load adjustment on the spring.
This is a drag engraving test with a non-rotating diamond tipped engraving tool -



Now I just need to make up a plate for the table that allows full use of the X/Y envelope for engraving and make an engraving vice for holding all the odd things that I get asked to engrave,
ATB,
Nick