My 4896 will arrive Friday! I’ve used one cnc previously, a Yeti Smartbench, which taught me a lot, namely I should have bought the Avid.
During my quest to improve accuracy, I build an 8020 frame inspired by the Avid. I built the width at 51 inches so I could have and inch of extrusion at the side to attach hold downs that I 3d printed. Fro. What I can tell, I could use the extrusion where the dust cover is along the Y axis by cutting a few holes in it. Would there be any downside?
On my previous setup, I added extrusion to support the entire frame of the spoil board and I see the Avid doesn’t support along the Y axis but some have added suport. Is this necessary? I’after 3 years of chasing accuracy and repeatability, I’d rather go a little overboard, but I do t want to be silly about it.
Lastly, the complaint I hear about the acids is they are light. My shop would never fit a prebuilt machine so the avid works for me.p, but I have a bunch of lead weighs from an old (to balance out a crane I put on). I wonder if mounting these would help, or maybe just bolting the legs to the floor?
Welcome to the wonderful world of CNC. Like you, I went with Avid because there was no way to get a pre-built machine into my shop. Also, they reviewed really well. I have a pro 4896 with Avid’s leg set. I built it per their instructions and have not added weight or bolted it to the floor. For working with wood, it is more than fine as far as accuracy and repeatability. I’ve had my machine for most of 6 years and been very happy.
The person on this forum who has thought a great deal about accuracy is Jim Neeb - he does intricate work with lasers and needs things perfect. He might chime in. He also has a Youtube channel (https://www.youtube.com/@JNWoodworks) that is work looking at.
I’ve got the pro 60120 with the Avid leg set, and it’s currently running a high speed carving of a delicate bit of inlay, with 0.005" passes. OTOH I used the lower leg braces to make a storage shelf for sheet goods, and have a couple sheets of MDF under there. Also, my “bed” is two sheets of MDF glued to each other.
So… I think you’ll have enough mass involved once you’ve kitted it out.
Bolting the legs to the floor won’t help. You can add weight up high in the frame, and crossbrace the frame to add stiffness.
However, the biggest improvement you’ll get is managing your acceleration settings, and since you are just getting your machine I’ll assume you have the EX controller. That is much smoother than the Mach4 setup, and gives you a lot more knobs to smooth it even further if you want to.
I use the Avid leg kit and have significantly increased the frame’s weight by adding a shelf under the spoilboard, where I store numerous plywood sheets.
As @jjneeb mentioned, the EX Controller has been a game-changer for me. I previously had issues with Mach4 on complex patterns, sometimes struggling to maintain accuracy. To compensate, I had to greatly reduce acceleration. However, since switching to the EX Controller, everything runs smoothly and much faster, without needing to adjust any settings.
Re-homing is also far more precise, and the ability to pause a job and resume it the next day with perfect accuracy is a huge advantage.
That has been one of my favorite things. I have been doing a lot of laser testing, and it is so nice to be able to power down, come back the next day and turn it on and home it and be exactly where I left off. All of my work offsets, laser settings, everything exactly as it was. Another nice thing is that if you don’t power down the Acorn, you can reload CNC12 as much as you want and not have to re-home it.
Of course, some CNC12 version changes require updating the firmware and in that case you have to power cycle the Acorn.
I added some additional extrusions along the bottom and and extra diagonals which helped rigidity somewhat. As @jjneeb mentioned, acceleration settings made the biggest difference.
Thats a great idea. Does anyone know what size the extrusions are? It looks like they’re 40 series from what I can see, but I’m finding them very hard to find in Canada now. It seems 45 series has taken over.
