[syn08]

Besides, even with backlash, your toolpathing strategy can eliminate it as a problem anyway. I am not talking about just turning on backlash comp (I never do, btw), just smart layout of how and from what directions you cut to minimize or eliminate the effects of backlash.

In particular for PCB milling, could you specify a method to optimize the toolpathing? I can't find any software that would automatically do that, and for reasonably complex PCBs that I'm trying to produce, manual optimizing is out of discussion.

[cameraguy]

In particular for PCB milling, could you specify a method to optimize the toolpathing? I can't find any software that would automatically do that, and for reasonably complex PCBs that I'm trying to produce, manual optimizing is out of discussion.

Hmm. Hadn't thought about that. PCB milling would be a different ball of wax to optimize.
What are your tolerances? Again, a relatively well-tuned Taig should be able to pull off most anything, but even if you can't for some reason, simply weighting the axes on a bone stock machine will solve 100% of the backlash problem. My buddy did that when he was doing a bunch of surface mount stuff just to be safe, but I don't think he really needed it.
Weighting is simple; For example, the Z axis cannot normally have backlash due to the fact it is weighted and gravity keeps it bearing on only one face of the screw all the time. Just do this to X and Y. All you need to do is add tension to bias your X and Y axes to one side or the other and backlash goes away on them is well. In doing so you are of course adding mass to each axis that will then somewhat slow your absolute acceleration rate for that axis, but that seems a very fair tradeoff for this specific application.

If you want a really elegant example, look here; http://www.cnczone.com/forums/84144-post2.html

That guy made all three axes weighted with one weight, taking extra weight off of the Z (counterweighting it), and adding weight to X and Y all at the same time. Very subtle.

My buddies was very much simpler and made entirely from scrap; It involved one cable on X and one on Y, each running to the nearest edges of the desk in his case, each going over a closet door roller at the edge of the desk for a makeshift pulley, and each cable with a 5 lb weight dangling over the edge. These were attached to an old drawer slides screwed to the side of the desk, just to keep them from swinging about as they ran up and down. Much like elevator counterweights.
Gravity takes care of 100% of backlash, and it cost all of $5 and maybe 40 minutes to make.

[syn08]

Hmm. Hadn't thought about that. PCB milling would be a different ball of wax to optimize.
What are your tolerances? Again, a relatively well-tuned Taig should be able to pull off most anything, but even if you can't for some reason, simply weighting the axes on a bone stock machine will solve 100% of the backlash problem. My buddy did that when he was doing a bunch of surface mount stuff just to be safe, but I don't think he really needed it.
Weighting is simple; For example, the Z axis cannot normally have backlash due to the fact it is weighted and gravity keeps it bearing on only one face of the screw all the time. Just do this to X and Y. All you need to do is add tension to bias your X and Y axes to one side or the other and backlash goes away on them is well. In doing so you are of course adding mass to each axis that will then somewhat slow your absolute acceleration rate for that axis, but that seems a very fair tradeoff for this specific application.

If you want a really elegant example, look here; http://www.cnczone.com/forums/84144-post2.html

That guy made all three axes weighted with one weight, taking extra weight off of the Z (counterweighting it), and adding weight to X and Y all at the same time. Very subtle.

My buddies was very much simpler and made entirely from scrap; It involved one cable on X and one on Y, each running to the nearest edges of the desk in his case, each going over a closet door roller at the edge of the desk for a makeshift pulley, and each cable with a 5 lb weight dangling over the edge. These were attached to an old drawer slides screwed to the side of the desk, just to keep them from swinging about as they ran up and down. Much like elevator counterweights.
Gravity takes care of 100% of backlash, and it cost all of $5 and maybe 40 minutes to make.

Interesting, thank you.

After being ripped by the cnc router machine, cnc kit - Taig Ballscrew BF20 5 axis milling thief I decided for a RedSail chinese machine with a 800W 25,000rpm water cooled VFC spindle. Short of the table build out of Al extrusions, which is absolutely crap, the machine is pretty decent. I'm now waiting for an Al cast 19"x19" T-slot table, guaranteed 1mil planeity.

After a little tweaking, backlash on this RedSail machine is virtually zero. My positioning tolerances would be ideally 1mil, worst case 3mil, as far as I can tell, 2 mil won't be a problem. My only concern is keeping this over time, I certainly don't entertain the idea of re-adjusting the thing every other PCB.

I'm using CopperCAM to import Gerbers, generate the contours and export the gcode. I have created a special test pattern (to estimate the resolution and accuracy on both X and Y, a picture is attached) and, experimentally, 20mils line and spaces can easily be resolved on both X and Y, asuming an 1mil table planeity over the entire PCB area and 30 degrees 4mil radius conical cutters.

So the Taig mill is currently off my plans, I have only posted here to warn others about the cnc router machine, cnc kit - Taig Ballscrew BF20 5 axis milling thief.

[Jeff-Birt]

I use CamBam for most of my PCB work now. It imports Gerbers directly and has very good path optimization. I would supply a link but every link I see to post gets squahsed by the admin. Just Google CamBam and/or Soigeneris

[cmadki4]

Sorry to thread necro, but I do want to weigh in on the cncconversionkit.com and conversioncnckit.com argument here. I've had a terrible time with this company/guy. He's just a small shop operating out of his garage and doesn't keep anything in stock, nor does have provide quality craftsmanship. I've been fighting this guy tooth and nail over the past month and a half just to get him to do the bare minimum. And I've had to just deal with some of the junk he has sent me.

Buyers beware! Do NOT buy from CNCConversionKit.com or ConversionCNCKit.com or the ebay store. Terrible company run by a guy with a terrible attitude.

Check out my complete thread about the ordeal w/ pictures here:
http://www.cnczone.com/forums/diy_cn...rsion_kit.html

[DLA_Dezign]

Sorry to thread necro, but I do want to weigh in on the cncconversionkit.com and conversioncnckit.com argument here. I've had a terrible time with this company/guy. He's just a small shop operating out of his garage and doesn't keep anything in stock, nor does have provide quality craftsmanship. I've been fighting this guy tooth and nail over the past month and a half just to get him to do the bare minimum. And I've had to just deal with some of the junk he has sent me.

Buyers beware! Do NOT buy from CNCConversionKit.com or ConversionCNCKit.com or the ebay store. Terrible company run by a guy with a terrible attitude.

Check out my complete thread about the ordeal w/ pictures here:
http://www.cnczone.com/forums/diy_cn...rsion_kit.html

Just to reiterate what one person said in that thread.......... WOW.....

Thanks for sharing the info
Dave

[cmadki4]

Just to reiterate what one person said in that thread.......... WOW.....

Thanks for sharing the info
Dave

Real nice, eh? It was an excruciating process dealing with that guy at cncconversionkit.com. Nearly everything he sent late and had a least one thing wrong with it. There are things I didn't even mention in that thread that just left me scratching my head.

- missing table extrusions
- missing spindle mount
- bolts roughly cutoff to fit
- tapped holes full of shavings and chips
- poor quality machined surfaces
- hammer-fit ball screw bearings too tight to turn by hand
- roughly hand filed and chiseled parts
- sent one used motor
- parallel cable not straight-thru
- control box a mangled pile of junk made on a band saw by someone who drank waaay too much coffee
- sent wrong power supply
- power supply mounted in control box with caulk!
- cheap motor cables only 5ft long
- shipped parts without giving tracking information
- over 30 days past promised delivery date
- bad attitude and criticized me and his other customers for being pushy and wanting their parts/machines
- had to fight him to give me refund for what he did not send
- all around bad craftsmanship and terrible concept of customer service (i get better service from the cable company)

Avoid like the plague....

[Winnfield]

Based on his pictures alone, considering nothing else, I cannot see a reason to buy from him. What was it about his product that motivated you to send him $$$? That isn't rhetorical - I am genuinely curious. When I look at his parts, I can't help but think that he doesn't care at all about what he is doing.

[cmadki4]

Based on his pictures alone, considering nothing else, I cannot see a reason to buy from him. What was it about his product that motivated you to send him $$$? That isn't rhetorical - I am genuinely curious. When I look at his parts, I can't help but think that he doesn't care at all about what he is doing.

It was a bad judgement call, for sure. But I did approach it cautiously and with the mindset that I would more than likely have to redo or modify what I got to some extent. However, I didn't realize how insanely bad some of it would be or how awful he would be to work with trying to get things resolved.

And that has turned out to be the case. I've done a lot to to make it into what is now a pretty solid machine.
- made my own motor cables
- made my own control box
- ordered a good parallel cable
- disassembled the base and gantry, cleaned up, sanded, retapped and reassembled properly and square
- changed how the table mounts to be more rigid
- redid the spindle motor wiring

Thankfully, I didn't pay the amount on his website. That would be insanity... If you factor in how much of my time he wasted trying to get things fixed and how much time and money I've put into make the turd he sent me a nice solid machine, then no, it wasn't worth it. But take the dealing with the guy and his crappy company out of the equation and I'm now happy with what I've got. NO THANKS TO CNCCONVERSIONKIT.COM.

[Bob La Londe]

That said - I still have to be convinced that the ball screw conversion does actually give any real advantage?

That is a big huge mixed bag, but there are a few things. The biggest is that for its reasonable life a ballscrew does not have to be adjusted. Also, a ball screw moves so much easier than a V-Lead or ACME thread screw that even if there was no other advantage you can run your machine faster. Backlash is pretty much predictable over the useful life of the screw with a ball screw.

[Winnfield]

It was a bad judgement call, for sure. But I did approach it cautiously and with the mindset that I would more than likely have to redo or modify what I got to some extent. However, I didn't realize how insanely bad some of it would be or how awful he would be to work with trying to get things resolved...

...Thankfully, I didn't pay the amount on his website. That would be insanity... If you factor in how much of my time he wasted trying to get things fixed and how much time and money I've put into make the turd he sent me a nice solid machine, then no, it wasn't worth it. But take the dealing with the guy and his crappy company out of the equation and I'm now happy with what I've got. NO THANKS TO CNCCONVERSIONKIT.COM.

I see. I wasn't being critical of anyone who chose to buy from him, I just wondered, with all of the options at that price point, why someone would buy from him. I contacted him early on about the ballscrew conversion, and his answer was so curt that I couldn't understand how he expected to ever sell them. He referred me to his YouTube video, and all it showed was him "checking" the backlash on one of the screws.

[syn08]

Interesting to see that scammer is still in business. As reported earlier in this thread, last year I had to sue his a** in a small claim court to make him deliver what he promised before grabbing the cash.

Reason for people still flocking in his claws are the reasonable prices and the sad truth that there's little to no companies in Eastern Canada that would convert a BF20 or Taig or SX3 to CNC with ballscrews, etc... or at least deliver a complete and good quality conversion kit. The people at https://www.machinetoolswarehouse.com seem to be trustful, they promised last year to deliver SX3's with CNC upgrade for a reasonable price, but it didn't happen yet.

Bringing conversion kits (not to mention complete CNC'd machines) from the US is a total rip off. Shipping, taxes, brokerage, right of brokerage fee, brokerage reimbursements, etc... etc... etc... are making any hobbyst to look first for local options. At least you can rent a truck and bring yourself the machine in your shop.

I'm hoping that Grizzly will sometime start delivering CNC versions of their G0619 and G0704 - they ship everywhere to Canada, at a very reasonable cost. Actually much cheaper than I would get a machine shipped from a local Ontario dealer!

[Bob La Londe]

I'm hoping that Grizzly will sometime start delivering CNC versions of their G0619 and G0704 - they ship everywhere to Canada, at a very reasonable cost. Actually much cheaper than I would get a machine shipped from a local Ontario dealer!

Do you think that Grizzly is likely to sell a complete conversion for those? They currently sell conversion kits for those, but they may not want to be responsible for the complete machine.

Grizzly.com® -- Product Categories

[syn08]

Do you think that Grizzly is likely to sell a complete conversion for those? They currently sell conversion kits for those, but they may not want to be responsible for the complete machine.

Grizzly.com® -- Product Categories

They must be joking, $2,500 before the machined ballscrews, for the SX3 mechanical side of a conversion kit? For the total cost (machine, conversion kit, electronics) plus shipping I can almost get a turnkey Tormach.

[cmadki4]

Oops, wrong thread. Delete.

[kdoney]

I just received the cnc conversion kit from cncconversionkit I bought and paid for on the 5th. The ad said the latest I would receive the item was the 15th. I should have been worried. I didn't receive the ball screws yet but I opened the other package and the quality really stinks. Bearing holes are not straight and some of the bolt holes are oversized. I can imagine what the ball screws are going to look like.

Be careful. This guy was always reassuring and promised anything that worked at the time.

[vingchocho]

this isn't the only thread warning about this guy.
http://www.cnczone.com/forums/diy-cn...75375-cnc.html

[rn2it]

Wow I just received my first three boxes of parts from CNCconversions and I will say I have not had a problem. as a matter if fact, I am [impressed with the quality of parts I received.
The ball screws are perfect, the cnc cut plates are great, the 80x80 extrusions for the side rails are clean cut and the spindle mount is very well made. I received my first three boxes in one week.
a couple of pictures of the parts, .Attachment 272274Attachment 272274

[Bob La Londe]

One (1)

[Sparkomatic]

Hi rn2it,

Did you receive the rest of the machine? How was the quality of the rest of it?

Also curious about the 80X80 rails, I though he only used 60mmX60mm?

I admit I have been considering purchasing from cncconversionkit for a while and only recently looked for reviews here. They do not leave me very encouraged with the quality and service however. ;-(

Cheers,
S.