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91
Project Logs / Re: Homebrew engraver to 3D printer Mod
« Last post by BillTodd on November 12, 2018, 05:35:33 AM »
Thanks Jeff , but all axes stop and the 12v rail disappears

I ran it last night without the hot bed and got a near perfect print (nozzle still leaking a bit). I switched to the blue painters tape as recommended by Don and it really seems to hold the print flat even without heat.

I think it must be spikes on the earth/ negative side of things . The board I have does not seem to have a separate 5v ground wire so will be reliant on the two 12v grounds which could be drawing 20+ amps peak , that's enough to cause some serious spiking/dipping of the 5v rail . 

Bill
92
Project Logs / Re: Homebrew engraver to 3D printer Mod
« Last post by chipenter on November 12, 2018, 03:00:03 AM »
The stepper drivers have thermal cut outs I fitted a computer fan , that stopped the dropped steps the board my have temperature cut outs .
93
Wood & Stuff / Re: What wood is this?
« Last post by Fergus OMore on November 12, 2018, 02:47:15 AM »
From a glance, I wood call it Borneo Red Seraya.

That was used in the 1950' to re-deck the whale factory ships on the Tyne. The Southern Harvester and the Southern Venturer, if I recall.

We used it for the framing of canvas kayaks- PBK's

It was also used as dunnage

OK

Norman
94
Project Logs / Re: Homebrew engraver to 3D printer Mod
« Last post by BillTodd on November 11, 2018, 05:27:47 PM »
No the stopping / power off appears random i.e it could be 3hours , 2 hours or as just now within a minute of starting to print  . I don't think it's the psu as it powers back immediately as the board is reset and it comfortably drives motors,  heater and extruder without dropping below 11.8v (measured on the board.)

I'll try running it woth bed heater as a test ...

95
Wood & Stuff / Re: What wood is this?
« Last post by raynerd on November 11, 2018, 05:23:43 PM »
Hi Pete, just canít find anything ...donít know where to look!
96
Project Logs / Re: Homebrew engraver to 3D printer Mod
« Last post by AdeV on November 11, 2018, 05:09:53 PM »
Just thinking out loud - does it always stop after around the same length of time running? Like an auto-power-off function, or some electronickery overheating?
97
Project Logs / Re: Homebrew engraver to 3D printer Mod
« Last post by BillTodd on November 11, 2018, 04:19:25 PM »
Well ths is getting very frustrating!!!


Auto tuned the pid of the bed and extruder  without any problems , added the values into the config  , and up popped an update  , libraies updated some error with U8glib , now it will not compile .

Apparently u8glib has bee superceded by u8g2 but i have no idea how to add this to marlin - any arduino experts handy???

Managed to add the pid values to the installed version using m304 p i d and run bed and extruder preheat perfectly

more frustrating is that the thing is still randomly stopping while printing - it just seems to swith the power off for no obvious reason - it is not loose connection as first thought but i have no idea atm whhatnis causing it  : :scratch:
98
Tools / Re: CNC Engraver
« Last post by AdeV on November 11, 2018, 03:04:20 PM »
Another update on this machine... I've got a couple more things to do:
  • Find a way of accurately locating the PCBs on the bed, so I don't have to arse about aligning them every time (anyone who's set up a job on a milling machine will know what I mean...)
  • Setup the Z-probe so I can do tool-changes mid-program.

Taking the second one first, I've identified that the tip of the tool is, conveniently, electrically connected to the body of the motor, which isn't connected to either positive or negative terminals. So I need to find a way of attaching the motor body to one side of the probe pin. For the bed, I can either use the copper surface of the PCB being drilled, or I could make a standard "puck" to do the job.

Anyway, having proved the probe actually works, I decided to do the first item instead.

So, the way this will work is: At a specific machine position on the bed, I'll mount a couple of fences, to which the PCB is aligned, before being stuck down with double-sided sticky tape. The first photo will make it clear (and if not, some of the other ones will put it beyond doubt!  :lol:)

First job, therefore, was to mill a couple of slots in that bed plate. To ensure they're dead straight and aligned with each other and the machine... I chose to do them on the machine itself  :bugeye: Remember how I said I didn't intend to do any engraving (let alone milling!) on this machine due to it's rigidity issues?  :loco: More of that in a moment...

So. Recently I bought a 2mm end mill for another part of this project. Seemed ideal! Plus it fits in the only ER11 collet I have, which is a bit of a Brucie Bonus. Mount it up in the machine, knock together a nice simple bit of G-code, Billy's your aunt, Fanny's your uncle, and everyone's very confused :D I decided on 0.25mm cut depth, nice slow feed rate of about 100mm/min, as I'm really not convinced this machine's stable enough for heavy cuts, even in plastic. More about that in a moment...

So, off it went! I videoed the whole thing, and once I get time to edit it & do the timewarp thing (who wants to watch a noisy machine vibrate it's way around an "L" shape for 15 minutes?), I'll upload it into a post below. Thus, no photos of the process. However, it seemed to go OK. Noisy, like I said, and lots of vibration. This really isn't any cop as a milling machine... but it got there. I suddenly realised (3mm into the slot, which I'd planned to be 5mm deep) that my cutter was looking awfully close to the tapered section. A quick scan of Arc Euro's website for the bit showed - yep, the one I've got has only got 3mm depth of cut! As it was already onto the 3.25mm cut, I let it finish that, and stopped it. Result is the first photo, after a bit of a clean up.

Next, time to get the real milling machine out, and make an aluminium fence. First, I cut a piece of 6mm ali down to 2mm, 0.100" DOC (like NASA, I like to mix up my units. Keeps everyone on their toes  :scratch: :zap:). Figured I'd better test it in the slot before I went much futher and... what's this?! Wibble-wobble! Break out the digital calipers and - crumbs! The slot is 2.3mm wide! Not good! That's where the lack of rigidity/vibration, or maybe it's backlash, shows up. So, if anyone was wondering, no: This is not suitable as a desktop milling machine...

Anyhow, this was no disaster for my purposes; I simply hacked off the 2mm bit & did a 2.3mm bit instead (I even got the old digital micrometer out for a bit of exercise!). After hacking it off the parent metal with the Deadly Dangerous Circular Saw From Beyond The Grave, and a bit of clean up, cut to length, repeat (the piece of metal wasn't long enough to do both), you end up with 2 tidy looking aluminium fences, per photo 2. These, gratifyingly, are a nice tight press fit into the slots, resulting in photo 3.

Happy days! Now I can simply line a PCB up to the two fences, stick it down, and I'll know it's exactly (to within the tolerances I need) where it should be! Plus, as it's only 2 sides, I can put different sized boards on without any hassle. As they're just push-fit, if I ever replace the bed, or need to drill a bigger board than I've left space for, I can pop them out, and either cut new slots on a new bed, or replace them once I'm done with the big board. (photos 4, 5)

All in all, a happy couple of hours machining :)

PS: Sometimes, the Chinese aren't too sharp with the PCB cutting tools... see photo 6 - this board's a bit wonky! When it comes to making the real thing, I'll probably use UK-sourced board, which I hope will be rather squarer cut! In fairness to the Chinese though, that's the only one that I've found that's out of kilter.

Next episode should be Z-probing, and possibly drilling an actual board!
99
The Design Shop / Re: CNC 4th Axis ideas needed
« Last post by mc on November 11, 2018, 02:29:00 PM »
djc, those are all valid comments, which have been bouncing around my head while thinking about the pro/cons of various options.

Chucks I'll admit I'm not entirely sure about. I'm actually thinking of something interchangeable, as I'd like to feed square/rectangular bar through the chuck, which would likely involve some kind of custom adaptable setup to allow for good flexibility, but then being able to fit a normal 3/4jaw chuck would be good for handling round bar. Some kind of D type chuck mount is a real possibility, although t-slots with a locating boss or two might be easier.

Running some figures from the top of my head, if I take a 50 tooth wheel with a single start worm, that's a 50:1 ratio. Couple it to a smallish servo (I'm thinking 2-400W) that should manage 3000RPM, that's 50RPS per second at the motor, and with the 50:1 ratio, gives 1 full turn of the 4th axis per second. Not exactly fast, but I would of thought perfectly adequate for occasional 4th axis machining.

If I'm being realistic, the majority of stuff I'll be doing will be more positioning than true 4th axis work, so I suspect a brake will end up part of the design just to eliminate backlash (I'm more concerned about chatter, than tolerances in that regard). And feeding an encoder to the KFlop to handle backlash is a possibility, but obvisouly minimising backlash to begin with is the better option.
100
How do I?? / Re: Power supply for Nema 23 Stepper ?
« Last post by Buell on November 11, 2018, 12:41:54 PM »
Clearly I shouldn't Go over 40vdc at 4amps  as thats all the Driver could handle ?
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