I've been bit, now how do I make this thing faster?

Coming from the heavily modified printer world, and diving into CNC has been an amazing journey. I built a regular 4x8 build and have done some quality of life improvements as far as dust collection goes. I would like to further improve that QoL with some sound deadening and rigidity upgrades. I have some thoughts, and I’m curious if the more experienced users would tell me if they are worth pursuing.

Currently using 23.4 emt conduit found in the US, would going to 1" OD tube of thicker wall make a difference? As for the thicker wall I am not necessarily looking for more rigidity than the standard OD tube would provide, But I am looking for more mass for greater DoC and Speeds, without lifting. I am looking at 1" .120 wall 4140

Would Foam or sand filling the Gantry and Y Rail reduce ringing? Sand in the X gantry might be extreme, but foam could be an option. Or sand in lower X rail, and Foam in the upper X Rail.

Reprinting the Rollers that attach to the YZ plates, and filling the infill with sand or lead shot. Again mass, Ideally Lower Down.

Steel YZ plates, again more mass.

Driving more weight might require stronger motors, which is a sacrifice I’d be willing to make for more reliable high speed cutting.

Am I way off base here?

If it is lifting something else might be wrong. Nevertheless, you could just stack weights on it. @azab2c did it for a job, but can’t find his post. :sweat_smile:

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I have 2 MPCNC’s here, and slowly building a third as a dedicated rotary lathe. I went with 1 inch DOM tubing with a 0.120 inch wall. I have very little “ringing” or flex. I push my machine fairly fast far faster then recommended. I can get up to 120 in/min without losing steps.
The trick with these machines that I have experienced is lower the step-down in your tool paths. In the 3d printer world that equates with finer layers.
Just my 2 cents

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For the longest time have been aspiring to build a Rockwool/fire rated drywall/green-glue/resilient-channel enclosure given trim router noise…

Complete with fancy polycarbonate pivoting door to bang my head on…

Lately though, am wondering whether it’d be just as effective, and cheaper time/material to just switch to a water cooled spindle (70db?), with NO enclosure. SteveMPotter has a nice setup, consider checking out.

My LR3 was doing wheelies while engraving polycarbonate. Not enough weight I thought… So I bought bunch of steel blocks at my local MetalSupermarket from their offcuts and scraps section. Each piece was 1-2lbs. Tried shoving different number of blocks into/onto the gantry. That helped a bit, until I started losing steps in part because my leadscrews were not well aligned and lubed, and my current was too low.
Unfortunately I was fixing the wrong problem, created new ones… Fortunately I discovered and fixed some existing performance bottlenecks related to my assembly quality.

Main cause for the lift and popping wheelies was me trying to use a symmetrical v carve bit. Unfortunately, the v bit has a flat tip and doesn’t pull through material like a new sharp 1/8" single flute uncut upcut carbide bit would. So the fix for me was to use a different bit, was engraving so specifically switched to an offset v carve bit, much better outcome thanks to JeffE’s suggestion.

During these misadventures I did observe that adding weight to the YZ plates (not the gantry), helped reduce unwanted lifting by using some Bowflex dumbbells. I understand not everyone has Bowflex, so maybe a :beer: six-pack holder for the YZ would be a more practical way to weigh down YZ plates.

Am switching from 4 start to 2 start leadscrew even though Ryan showed off how much weight a well assembled stock LR3 can handle.

Curious what combination of bit, material and speed is causing unexpected lifting? Have seen suboptimal and/or dull bits burn a bunch of people’s time.

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Aza, you were undoubtably my inspiration, for the adding mass to the machine. To be honest i cant remember what particular set of events was leading me to lift. I think it was possibly trying to surface some black walnut a little too enthusiastically.

That said PC/acrylic are defininitely on the agenda.

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I’d like to see some details on the MPCNC dedicated rotary lathe build if/when you get that going.

Can you be more specific on what you did to improve the quality of life on dust shoe/collection for the LR3? I have mine set up with an actual dust collector that pulls a lot of air, but just isn’t grabbing the wood particles as it passes, even when directly over the pile. I feel like it needs to be close to the bit and the surface, maybe a brush around the head would help?

In some traditional CNC builds, I have seen some YouTube videos where the maker of the CNC would achieve adding mass for both strength, rigidity and deadening against vibrations/ringing, by filling cavities in the CNC components with concrete or an epoxy-concrete mix. I suppose one could disassemble the gantry, plug one end of the EMT tube/DOM tube, and then stand the tube up on its end and use a funnel to pour concrete into it. If you did, you would probably have to use a ramrod to make sure the concrete got pushed all the way through. I’m not recommending this. I’m just thinking out loud in response to your questions about adding mass.

I know a guy with a cnc plasma cutter and I thought about having him cut me a set of strut plates from 1/4” steel to add more weight and rigidity, but then he quoted me a price and I cut that delusion short. :rofl: :joy:

I think regarding speeds I am doing pretty well, I went 6mm deep with 2000mm/min in hardwood with a 6mm 2-flute, there is no lifting.

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33mm/s at 6mm doc? In hardwood? Speedy!

I’m still running 25/2 because I’m a coward lol

Hmmm… Sounds like you still need a mohel…

:man_facepalming:lol, fixed my typo, that was faster less painful option than fixing me. Cheers!

Been held up on the rotary build for a bit, health issues. Old shoulder injuries have caught up with me.
Being 60 doesn’t help either

I’m not there yet but I feel your pain! I’m definitely not in my 30’s anymore…

Let us know when you get around to working on that rotary build.

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