Making your own panels with a desktop CNC

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nateflanigan
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Re: Making your own panels with a desktop CNC

Post by nateflanigan » Fri Sep 04, 2020 9:05 pm

Hello hello hello

I've made some upgrades to my rig, not the sexy stuff but serious improvements.

First a welder buddy gave me this machine table, it is WAY more stable than the work bench I built out of 2x3's (which isn't a piece of junk by any means)
Image

Second I bought this "home made" dumb bell from a welding/metal supply shop, it does a great job of holding down and flattening the panels while the glue sets up.
Image

I bought a few of these bits.
https://www.ebay.com/itm/30-degree-angl ... 2749.l2649

I ran a some cuts yesterday and tonight implementing a few things I've learned as far as setting up tool paths. I think the results are much better, and the job seemed to go smoother overall.

- I added 2 deg ramps and a finishing pass, much much cleaner results.
- I tried a few different types of lubrication, wax didn't really work well, the very fine black chips from the paint got stuck in the engraving. I was mostly able to clean it up with a tooth brush and mineral spirits though, kind of a pain. Then I did another one with just wd-40 that worked pretty well.

I'm still messing with infilling, one thing I've found is that the haze really stains the matte black paint on the dotcom panels very easily. So, I'm trying something out, I did a light wipe of shellac before machining. Hopefully that'll let me wipe up the haze more easily.

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Re: Making your own panels with a desktop CNC

Post by nateflanigan » Sat Sep 05, 2020 8:45 pm

Getting a bit better at infilling, My shellac idea worked out ok, could use a bit of refinement.

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devinw1
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Re: Making your own panels with a desktop CNC

Post by devinw1 » Sun Sep 13, 2020 11:24 pm

So, I finally got around to making a panel with my CNC6040. I replaced the entire flimsy aluminum extrusion deck with a solid piece of precision ground 25mm thick 6061 that I had a machinist friend make. This made a huge difference in the machine and cut down a lot of vibration and increased the rigidity. Here is the major heavy duty slab with a MDF spoil board on top:
router.jpg
ANYWAY, cutting Aluminum is going fantastic now (holes, outline, etc.), but I'm still hoping to get better results engraving. I used this bit:

"ENPOINT Metal Engraving Bit, 20 Degree Engraving Bit 1/8” 3.17mm Shank 0.5mm Tip 38mm Total Length 2 Flutes Tough Tip Cone Carbide V Bit Marking Conical V-Bit for Aluminum MDF Wood Brass " from Amazon

Which claims to be 0.1mm tip, but my results seem to suggest it is bigger than that (more like 0.15 or 0.25mm). I bought two of them and I will take them to the metrology scope at my work office and measure them to see. In the meantime, you can see below the letters are all too "chubby" leading me to believe the tip is larger than 0.1mm. Also, the surface finish inside the letters is kind of not great. Any tips on feeds and speeds for engraving would be most appreciated!

Oh yeah, I also tightened down too hard on my work clamp and bent the corner as you can see. :doh: :doh: :doh: :doh:

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Re: Making your own panels with a desktop CNC

Post by jimfowler » Sun Sep 13, 2020 11:34 pm

well, tip diameter is only one piece of the puzzle. included angle (ebay listing says one thing, image of item says another) and depth of cut are critical too. but yes, if your tip diameter is not what the machine thinks it is cutting with then your shit will be all kinds of off.

for this kind of milling i use (and therefore recommend) a tipped off engraving endmills. i use harvey tools. if i'm unsure as to F&S for a tool i'll usually look up their recommendation for a similar tool and go from there. that looks like a marking cutter so perhaps start with harvey's data.
Last edited by jimfowler on Sun Sep 13, 2020 11:48 pm, edited 1 time in total.

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Re: Making your own panels with a desktop CNC

Post by devinw1 » Sun Sep 13, 2020 11:46 pm

Thanks for that Reco, Jimfowler... Those tipped-off engravers look NICE . Lots of rigidity due to having the full diameter on half of the tool.

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Re: Making your own panels with a desktop CNC

Post by jimfowler » Sun Sep 13, 2020 11:51 pm

incidentally they describe their marking cutters (2-flute) as being stronger than their normal engraving cutters. i've had really good results (both in part finish and tool durability) with 0.010" tipped-off engravers. i might try a marking cutter to see if i can move things along a little faster...

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Re: Making your own panels with a desktop CNC

Post by devinw1 » Mon Sep 14, 2020 12:04 am

Oh nice. I'll have to see if they have those in .005" tip too. .01 is cool, but I'd prefer to try an approximate square font corners a little more of possible. More passes of course tho. :-/

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Re: Making your own panels with a desktop CNC

Post by KSS » Mon Sep 14, 2020 6:13 am

Spindle runout adds to cutter diameter. AKA effective cut diameter is nearly always more than than measured cutter diameter.

Machine structure rigidity and linear and leadscrew bearing play-preload factors in also.
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Re: Making your own panels with a desktop CNC

Post by jimfowler » Mon Sep 14, 2020 7:42 am

devinw1 wrote:
Mon Sep 14, 2020 12:04 am
Oh nice. I'll have to see if they have those in .005" tip too. .01 is cool, but I'd prefer to try an approximate square font corners a little more of possible. More passes of course tho. :-/
they do. that’s the smallest one they make i believe.

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Re: Making your own panels with a desktop CNC

Post by devinw1 » Mon Sep 14, 2020 10:36 am

KSS wrote:
Mon Sep 14, 2020 6:13 am
Spindle runout adds to cutter diameter. AKA effective cut diameter is nearly always more than than measured cutter diameter.

Machine structure rigidity and linear and leadscrew bearing play-preload factors in also.
For sure. I also just realized I didn't factor the effective increase in diameter at the surface where the Ano is cut due to the depth of cut. It's worse the higher angle cutter you go. With a 30 degree tool and .05mm DOC, the diameter at the surface is .13mm, not .10mm. I couldn't figure out how to get the engrave feature in Fusion to do what I wanted so I just used pocketing and said it was a .10mm straight tool, so this would affect it.

I just ordered a harvey 993215-C8 and 834308-C3 so we'll see how that works out.

I'm also in the process of accumulating parts to re-do the other weak link in this machine: the unsupported rails on the gantry axis. I have a design all cooked up to switch the gantry and Z axis to 25mm and 20mm Hiwin box type linear rails and upgrading the long axis rails from 16mm supported to 20mm supported at the same time.

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Re: Making your own panels with a desktop CNC

Post by KSS » Mon Sep 14, 2020 1:31 pm

Remember that you generally want to use the largest diameter cutter you can. Better tool life and more importantly in this class of machine, lower required speeds and feeds.
------------
Sounds like you're rapidly approaching diminishing returnx. AKA gilding the lily. Before you do those linear bearing upgrades you'd be wise to look into your leadscrew mount and drive nut realities.

The already fixed 16 move to fixed 20 isn't going to give you much worth having. Don't forget the effect of added weight and mass on the performance of your machine! Bigger is *not* always better. Along with added weight are overhangs and cantilevers which may increase with larger -or supported- rails. These may make it all worse. It's a little like putting a Hinton supply in a stylophone.

It's still going to be a cheaply framed aluminum machine efter you do the upgrades. Be sure they're worth the effort. Some you've described may not be.
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Re: Making your own panels with a desktop CNC

Post by devinw1 » Mon Sep 14, 2020 1:43 pm

KSS wrote:
Mon Sep 14, 2020 1:31 pm
Remember that you generally want to use the largest diameter cutter you can. Better tool life and more importantly in this class of machine, lower required speeds and feeds.
------------
Sounds like you're rapidly approaching diminishing returnx. AKA gilding the lily. Before you do those linear bearing upgrades you'd be wise to look into your leadscrew mount and drive nut realities.

The already fixed 16 move to fixed 20 isn't going to give you much worth having. Don't forget the effect of added weight and mass on the performance of your machine! Bigger is *not* always better. Along with added weight are overhangs and cantilevers which may increase with larger -or supported- rails. These may make it all worse. It's a little like putting a Hinton supply in a stylophone.

It's still going to be a cheaply framed aluminum machine efter you do the upgrades. Be sure they're worth the effort. Some you've described may not be.
Totally understand on the cutter thing. But, i'm talking engraving here. You want squarer corners in the letters, you need tiny cutters. Tis the way it is. .005" tip engravers are certainly not a rarity though.

You're right about the upgrades though. I'm trying to do things on the cheap by making parts that make sense, etc.. The existing gantry unsupported rails are actually really heavy, you can actually see the sag of them when running a mic across the full gantry travel. I'm guessing the box rails I've found are actually lighter than that whole combination. They will just need a plate to bolt to which is rigid enough to support them but also not too heavy. I think I can engineer this.

I do disagree with you on the long axis rails though. Those are part of the very base of the machine and actually contribute to the base frame rigitidy, but are not part of a moving or reciprocating mass. I don't see how increasing the section modulus of these rails could hurt. THough, it may only be a marginal improvement. They were cheap though, and give me a chance to dial in the clearances and lubricate the slides while I'm there.

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Re: Making your own panels with a desktop CNC

Post by KSS » Mon Sep 14, 2020 2:08 pm

|=|=======================================|=|

vs

|=|=|=====================================|=|=|

One wouldn't -or shouldn't?- expect round rails supported at their VERY ends *not* to sag. Look into how tightly they fit in the end plate holes. Consider making a doubler plate which fits TIGHT -think heat-shrink fit- and put that on the inner side of the end plates. You lose a little travel, but the stiffness goes up *significantly*
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Re: Making your own panels with a desktop CNC

Post by devinw1 » Mon Sep 14, 2020 3:50 pm

Yes, it's true, this is not a texbook simply supported beam, it has some constraints on the ends and is dependent on the end plate structure. And your idea would definitely help that.

I guess though, considering the price you can get decent square rails for, which are already preloaded, it seems easier. It is quite well known that square rails have less deflection than (even supported) round rails:



On the other hand, I've probably already thought about/worked on this this too much and should have just bought a Haas. :D

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Re: Making your own panels with a desktop CNC

Post by nateflanigan » Wed Sep 16, 2020 8:26 am

@devinw1

I have no business offer anyone advice, but maybe try a single line font for the smaller text, in my opinion they come out better. Are you planning on infilling?

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Re: Making your own panels with a desktop CNC

Post by nateflanigan » Wed Sep 16, 2020 8:42 am

I found a couple hundred bucks I forgot about in my venmo and went on a cnc shopping spree. I now have a mister, some more aluminum to play with, a diamond drag bit, and should be receiving the Harvey tipped off bits and an 1/8 collet today.

The diamond drag is cool, here's some initial tests on a clear anodized eurorack panel and infilled with blackeneing solution. I used the quick engrave toolpath in vcarve, the DOC, or pressure is .2mm which is the lightest the manufacturer suggested. Feed rate 20 ipm, all I could find for recommendations was to go slow, but no guidelines for what slow means... :despair:

The text is 2mm as advertised, the dxf dial scaled a little weird and I didn't bother to fix it so the numbers are TINY. If you zoom in it looks like crazy garbage but at a normal distance it looks cool, has a sort of old military/industrial vibe.

Image

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Re: Making your own panels with a desktop CNC

Post by devinw1 » Wed Sep 16, 2020 10:15 am

nateflanigan wrote:
Wed Sep 16, 2020 8:26 am
@devinw1

I have no business offer anyone advice, but maybe try a single line font for the smaller text, in my opinion they come out better. Are you planning on infilling?
Thanks, yeah that's not a bad idea. I do not plan on in fill since I'm always using pre-ano panels for contrast. These are all prototypes, so quality doesn't need to be insanely good, but I do think I can do better than my first shot!

I too bought some new tools which are on the way. I'm excited by the Harvey Marking tool. Looks really nice. Also I think making sure the depth/diamter is compensated for in Fusion should help.

The diamond drag results you got look promising. Looks like it is able to do some really small stuff. Definitely has that old school vibe/industrial/military!

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Re: Making your own panels with a desktop CNC

Post by revtor » Wed Sep 16, 2020 12:38 pm

Nate that diamond drag blackened font looks pretty good.. It would take a bit of work but you might be able to do some cool things with a pseudo-infield graphic type of fonts on a larger scale.
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Re: Making your own panels with a desktop CNC

Post by uniqview » Wed Sep 16, 2020 11:38 pm

Thanks so much for this report! Got me thinking about lots of options!
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Re: Making your own panels with a desktop CNC

Post by KSS » Thu Sep 17, 2020 6:57 am

@nateflanigan
Try diamond drag on a non-anodized plate. Doesn't have to skip through the 'sapphire' honeycomb that way.

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Re: Making your own panels with a desktop CNC

Post by nateflanigan » Mon Sep 21, 2020 7:04 pm



Took a big step forward this afternoon and cut a Buchla style panel out of 0.063" 6061 aluminum. Cut with a Diabolo router bit from home depot.
https://www.homedepot.com/p/DIABLO-1-4- ... /100660697

I used really conservative settings and the cut came out very nice. 0.01" pass depth, slowest setting on the router ( ~16,000 rpm) feedrate of 32 ipm. 0.001 chipload, Six passes of conventional cut then a finish pass of climb cut. 2 deg ramp on each pass, lubricated with a mister from amazon, the collet was warm to the touch but certainly not hot. Job took about 5 minutes to run which is fast enough for me, it's not like I ever plan to crank these out.

It looks like the machine is working a little harder on the ramps (at the top of the panel) but I think it's just that the plunge rate is slower than the feedrate.

I assumed this would come out poorly, guess I should engrave some actual text on it, maybe I'll end up with a nice panel.

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Re: Making your own panels with a desktop CNC

Post by devinw1 » Tue Sep 22, 2020 10:35 am

Sweet. I cut another panel last night too. One discovery I made early on is GET NICE TOOLS. Seriously. I am buying carbides from Lakeshore Carbide now (made in US!) https://www.lakeshorecarbide.com/ and honestly not that expensive ($10-$15 each) and they are so much better than any of the chinesium bits I've ordered online in terms of sharpness and performance. The variable helix mills are especially a real treat!

Are you using Fusion for your code? If so, in my limited experience, I highly recommend using Adapative clearing to rough around the edges, then do a final finish pass. You just have to simply do a offset sketch on you edges to give a virtual island of material that is wide enough for the bit to do the work:



What you are doing is basically slotting, which is one of the hardest things to machine, since the chips can't evacuate easily. I have been doing mine like that with a 2 flute carbide 1/4", and rip through full depth of the panel in no time and the machine doesn't mind at all.

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Re: Making your own panels with a desktop CNC

Post by devinw1 » Wed Sep 23, 2020 11:39 pm

I thought I'd also report on my results from testing some new engraving tools/settings. I tried 3 different tools, and also offset the program to the actual diameter at the top of the anodize (which is larger due to the tool being V shaped). Tip diameter is .13mm on all 3 tools, and I made code for a "tool diameter" of .15, .17 and .19mm. I would rate them as follows (they are in this order on the image, top to bottom). This is all 2mm tall "filled" text, not single stroke. Note, the "ghosting" around the 9 and some other areas is a camera artifact, not in the text engraving:

-Harvey tool HTC 834308-C3 Double tip, tipped-off engraver 30 deg, .005" tip: A- , very sharp
-Amana tool 45632-K 45 deg tipped-off engraver, 1/4", .005" tip: C, not super impressive!
-Harvey tool HTC 993215-C8 30 deg "marking tool", 30 deg, .005" tip: A+, best of the lot. Thanks for mentioning that one!

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Re: Making your own panels with a desktop CNC

Post by nateflanigan » Thu Sep 24, 2020 1:03 pm

Both the harvey tool cuts look great to me, is that single line text or a pocket cut?
Are you using Fusion for your code? If so, in my limited experience, I highly recommend using Adapative clearing to rough around the edges, then do a final finish pass. You just have to simply do a offset sketch on you edges to give a virtual island of material that is wide enough for the bit to do the work:
I use vcarve but am familiar with 360, vcarve has a similar toolpath function.

I've been working on this the past few days...

Image
Image

I used the fpd file on fluxmonkeys site and tweaked it to use single line text, engraving with the 0.005 tipped off harvey bit, 0.2mm deep conventional cut then a 0.22mm deep climb cut for a finish pass worked pretty well. I still have some issues with getting the panel perfectly flat and I think I was running slower than necessary but I'm pretty pleased. The thing I'm stuck on is infilling, using a markal B paint stik, I rub it in, then right away wipe with little pieces of paper, sort of pushing the paint into the cuts even more. This works really well, but then I waited overnight to try to remove the haze with mineral spirits, that didn't go so good, had to touch up with some more paint. I waited a while then very delicately cleaned it up more with solvent dampened paper. That worked ok but there's still haze, I'm not sure how long to wait or what to wipe with next. I called markal and they said it dries in 12 hrs and cures in 24. I'm thinking maybe apply, wipe with dry paper, 12 hrs wipe with solvent, then at 24 I dunno, maybe cleaner wax?

If I could get this step right I'd be pretty happy. Also, I gotta say the buchla style panels lend themselves to this way more than the dotcom panels. Might need to change up my format.

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Re: Making your own panels with a desktop CNC

Post by devinw1 » Thu Sep 24, 2020 1:13 pm

Looks good with the infill! I would say though 0.2mm is pretty deep for a engraver. I am only going .05mm myself. You might want to back that off a little. Looks like you got a little chatter in there? What are you RPMs and IPT?

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