posted
I think Rusty's right. I noticed that plotting was mentioned a couple times.
-------------------- dennis kiernan independent artist san francisco, calif, usa Posts: 907 | From: san francisco, ca usa | Registered: Feb 2010
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posted
Speaking of plotting...I did make a plotter-blade holder for our router. You can plot through the coversheet of Alupanel etc, then weed it off, scuff and paint. Makes for some decent profits, especially with the 10 x 5 ft sheets.
[ July 01, 2015, 10:08 PM: Message edited by: Ian Stewart-Koster ]
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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posted
That sounds like a handy invention, Ian. Does it chuck into the router's collet? How do you control the downforce? Compression spring?
Rusty and Ian, We were all geared up for using our code in plotting to sneak our blades and long axes through the weeds with a coversheet but decided to take another route because the timing was wrong and there would be too much backlash.
-------------------- Wayne Webb Webb Signworks Chipley, FL 850.638.9329 wayne@webbsignworks.com Posts: 7403 | From: Chipley,Florida,United States | Registered: Oct 1999
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posted
There should be lots of cheap cover cheets with big red crosses full of stars available soon, Wayne...
There are commercial plotter blade holders that go in the chuck, and have a spring-loaded blade for pressure - but I have an aluminium bracket that pokes out the front of the spindle, and that holds the holder when I need it to.
The holder is a bit of 1-1/4" steel rod with a 3/8" hole up the centre, and weights on top, and a Roland blade holder on the bottom. I made a worse looking one before settling on a better one.
It's offset from the spindle centre by about 8mm in Y, and -115mm in X. IN the driver software It is set up[ as a different tool (tool #1) with an offset of -115,8, compared with the spindle which is tool#2 on 0,0.
Alternately you just tell it to do everything with respect to a different origin, which is -115,8 compared with the normally selected & saved origin.
I used to add washers & nuts till I was happy with the weight on the knife. The cnc just lifted it high enough up to clear the substrate by 10mm when travellng to the next pen-down point. I'd set a cutting depth of 1mm, and so the spindle would drop, and the blade would drag, weighted by washers.
The only difference compared with a plotter is you don't get perfect 90 degree corners, as the plotter blade just follows where it is sent, like a caster wheel on a trolley or chair.
I toolpath it as if it's a 1/32" diameter endmill, male/external path and it mildly rounds or radiuses corners, but that is no issue at this scale. (A plotter will overshoot the corner by the blade offset then back up and change direction, for perfectly 90 deg corners etc)
Also you have to set the start & end points of a perimeter path to overlap by 3mm, to be safe. If you do not, then the minute offset of the blade point will give you tiny tags of background that make weeding a nuisance.
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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That's a pen that'll go in the router collet/chuck, but I've done a pen that takes a parker pen refill, and replaces the plotter blade holder - so you can draw big patterns easily - without needing a projector.
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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Here's a thread about making one to work with a stanley knife blade - but mine is nothing like that - way simpler.
I'll try and remember to get some photos tomorrow.
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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Here are the two plotter blade holders, and a biro refill holder (top):
Close-up pic of the tips - with standard Roland 30 degree plotter blades - from Ebay - HongKong.
This is the better of the two holders,(the middle one from the top pic) sitting in position in blocks in the aluminium holder in front of the green 3HP Perske router spindle:
This shows me lifting the top up - those are some weights masking-taped together with cream masking tape, and they sit on the slidable blade holder, to provide weight to the blade.
There is about 3/4" of travel up & down in the slider part, so lifting the spindle 1" after every stop, will make sure it clears the substrate by 1/4" as it travels to the next pen-down point. Setting it to 'rout' at 1mm deep means that the entire holder is lower than the travel of the blade holder, so that gravity plus the weights on top do the cutting and the spindle head just steers it.
This shows the gantry - the Y axis. There's about 2 metres in bed capacity width - and the rack is visible on the side. There's a tin box over the servo & gearbox etc at the far end - and you can just see the green Perske spindle at the end, beyond the servo cover.
Hope that helps!
[ July 06, 2015, 03:41 AM: Message edited by: Ian Stewart-Koster ]
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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I have a slight hurdle to get over: When I tried machining just one surface of the 90° "V" on one side of an aluminum flat bar to make one of the two y axis guides, the flat bar warped as crooked as a dog's hind leg. The aluminum built up heat much more easily than expected and that flatbar is totally unusable for a guide now. I was trying to get around using steel, like I did for the x axis, because the Y will be moving and it's weight/mass would increase the g forces on the drive belts causing backlash. But I may have to if I can't find a suitable alternative.
I'll see if I can find some extruded ones but that will mean I will have to re-design and re-fabricate one or two of the parts I've already made. Oh well, I'm this close so there's no need to quit now.
-------------------- Wayne Webb Webb Signworks Chipley, FL 850.638.9329 wayne@webbsignworks.com Posts: 7403 | From: Chipley,Florida,United States | Registered: Oct 1999
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posted
Wayne, the gantry rolls along the X axis by rolling along some 1-1/4 diameter rod on top of the box section. Under the gantry is a pair of bearings at 12 o'clock and 3 o'clock at the left side, and at 10 and 2 o'clock on the right, I think. There's a back brace on the left also. Gravity does the rest of the work.
The router head and Z axis stuff runs a bit differently. ON the gantry are 2 bits of about 1" or 1-1/8" diam rod going left to right - one on top of the box section and one underneath. The head or Z axis runs on 2 ordinary big sets of bearings against the top rod, and 2 against the underside. They're all mounted in a V orientation, i.e. at 10 and 2 o'clock on top, and 4 & 8 o'clock underneath.
I hope that makes sense!
As for the plotter blade holders - the first one was some domestic copper water pipe, drilled and an ebay plotter blade holder epoxy-glued in the end. That was then attached to another rod that slid up and down with negligible wobble inside another bit of pipe I had in the spare parts heap. The outside was packed up with polypipe to gain the diameter needed to fill the aluminium block that holds it all. So most of the stuff you're looking at is spacers.
The blade itself and the holder have the ability to slide up and down a bit. Stoppers limit the movement. The 2nd plotter blade holder - the black one - has linear bearings in the tube, for the up-and-down part to slide in with no unwanted wobble left or right.
The tube has plastic waterpipe around it to take up the space needed to fill the aluminium holder.
Hope that helps!
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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It's really made the production of painting bigger signs on alupanel etc, very profitable for us - by cutting the plastic cover sheet. You then weed it, scuff it, paint it, and if needed, brush an outline or shade, etc - no vinyl needed, no app tape needed, and very time-efficient, once you have it designed.
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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posted
Sounds very interesting, Ian. How do the carbide blades hold up dragging over that aluminum? Do you use a carbide plotter blade?
I ordered some 'storebought' linear rails from Openbuilds http://openbuildspartstore.com/ They're a little thin and not exactly what I wanted but, they are precision made and maybe they will work if I screw them down good about every 3". They don't have to carry much weight anyhow.
-------------------- Wayne Webb Webb Signworks Chipley, FL 850.638.9329 wayne@webbsignworks.com Posts: 7403 | From: Chipley,Florida,United States | Registered: Oct 1999
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posted
Yes, Wayne - 30 degree carbide or carbide tipped blades. They hold up fine - just watch out if the file needs it to run past the edge of the sheet though or you'll break it on the return journey!
I have a fine diamond grit sharpening file (well, a few of them). If I think the cutter blade tip is getting dull, I just put it in the vice, and go over it with the file. That might sound crude, and others might say you're losing the accurate offset measurement, or they're cheaper from china etc etc, but I can get a year or more of life from a blade, with minor touchups like that, and whether your blade offset is 0.25mm or 0.3 or 0.5 or more, in an 8x4 sign seen from 10 feet at the closest, the plotted difference is negligible except in the corners, and I use an offset path with minutely rounded corners anyhow, so the blade easily trails like a caster wheel.
It only takes a minute to freshen the blade - and you can check it with a jeweller's loupe. Never as good as new, but servicable - it is the tip of the point and a smidge ahead of that which does the work anyhow, nor the shiny faces on each side.
The blades do dull quickly if cutting the cover sheet on what we call colourbond steel - and there';s a sign product in that which I used to use a lot, but the aluminium os relatively soft - besides you're not trying to cuit the Al, just cut the cover plastic sheet- that's why there are adjustable weights on the centre top, for pressure variations as required.
[ July 13, 2015, 10:07 PM: Message edited by: Ian Stewart-Koster ]
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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various paints: Duraguard low-sheen waterbased UV stable for some black (you might call it latex, but here, latex is junk - we call it acrylic - but it's not acrylic like, lacquer. It's water based house paint. & Enamel - standard stuff & 2-pack urethane for some
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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posted
Sorry, Rusty, I'm having too much fun routing the law...
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"...there are no limits when you aim for perfection..." Jonathan Livingston Seagull Posts: 7014 | From: Highgrove via Toowoomba, Queensland, Australia | Registered: Dec 2002
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