Over the weekend I have been lurking and reading some of the posts here and would like some of your comments on a faceoff between the LR3 vs. a WorkBee/QueenBee/etc.
I am a newb to the world of CNC kits but I do have experience with 3D design, 3D printing and other self made projects. I am looking at buying/making a CNC machine for mainly straight edged profile cutting of 2D parts in various materials about 6-12mm thick. I started researching typical WorkBee/QueenBee kits before discovering the LR3 and the more I look at the details of the LR3 design the more impressed I am!
Some benefits of the LR3 I can see are:
Much lower build cost
Can cut full sized 2.4 x 1.2m sheets without the need of tiling
Can be stored away more easily and efficiently when not needed even though it is a bigger machine
Obviously the more expensive WorkBee type CNC kits must have some advantages which I am only guessing might be:
More frame rigidity and potentially faster cutting of hard materials like aluminium?
Better for milling 3D parts with more Z height? (as against straight through cutting of 2D shapes)
With bigger NEMA 23 motors used perhaps the cutting power of these machines is greater?
Again these are just my thoughts not based on any real experience…Please add your thoughts to either of these lists.
My main question though is what might be the difference when profile cutting some 2D shapes out of 6mm MDF/acrylic plastic/HDPE? I am not fussed if the cutting speed is lower but is it possible an LR3 machine could produce a high quality, clean cut as good as a WorkBee….?
Not necessarily, it’s more expensive primarily because it uses more expensive components.
It’s more similar to a Primo MPCNC than a Lowrider from the pictures.
Welcome to the forum by the way. If there’s anyone who has both machines here hopefully they will give their experiences.
LowRiders have been used successfully for cutting not only aluminum but even steel. Here is a pic and link to a thread in which a LowRider is being used to cut quarter inch thick aluminum at full depth of cut (with trachoidal milling).
In making my LowRider, I followed the example of Dan, @SupraGuy, in making my YZ plate taller than normal. I have yet to actually use that extra height other than just getting better access underneath the unit for bit changes and cleaning. However, I’m confident that if I wanted to do some 3-D shaping and cutting, the LowRider would perform well within that added height.
I am a huge fan of the LowRider. In my estimation, it is the perfect balance of capability, strength, rigidity, and affordability.
I have never seen any head to head videos but I am confident most good hobby CNC’s ($5k and under) perform very very similar. I used to watch a lot of CNC videos and have never really seen anything that has made our machine feel any less effective.
We gain a lot of cost saving is the fact we use inexpensive Steel tubes instead of expensive aluminum extrusions and the pricey fasteners that those need. Performance wise, if you look at a lot of the power users in any hobby machine you will see the material removal rate is very similar.
We have seen no reason to move up in stepper size here. I actually ship them configured for an extremely conservative power setting and if for some reason you needed more power you can simply turn them up, no one does though. I am sure some of those machines are using larger components just to seem beefier, to satisfy user requests. Ball screws, linear bearings, giant high current steppers, all are not going to benefit you much until you get into a very large steel frame, they just cost more money.
Hehe I like the MORE POWER!! reference. Always seems a good idea…
At this point I am pretty much sold on the idea of building a LR3 and seeing how it goes. I love the idea that it can cut a full size sheet and it seems you guys are getting some great results. I am not looking to machine complex 3D parts with high Z depth and nor do I care much if a lower cutting speed is used for better quality. It seems tuning the cutting parameters and doing a final finishing cut is more important to getting a good cut quality.
At first I was thinking the linear rails, ball screws, etc found on the WorkBee might mean better cut precision but I haven’t used either machine so your feedback is much appreciated.
I know this is somehow a shameless self promotion, but if you check out the things I made with the Primo and LowRider in the gallery you will see it’s pretty versatile. I have also cut 6mm deep in one pass at 2000mm/min. It’s not beautiful but it works.
Exactly, and this is true for every machine. Even if another machine was better for say $800 more, would saving 5 minutes and hour really be worth it? None of the other machines will cut your time in half until you get into something like an Avid, even then maybe twice as fast is a lot.
These tend to need a lot of maintenance as well. They will bind completely if they get too dirty so they are slightly better but they come with tradeoffs.
For my use I agree that a 5 minutes per hour increase in cutting speed is not worth it.
Locally we get HDPE sheets in 3.0m x 1.5m sizes and higher quality “Boatboard” HDPE is 2.44m x 1.37m. Is increasing the X-gantry for up to 1.5m cut width asking too much? I expect it would add a significant amount of extra flex in the gantry beam. Of course I could just cut any larger sheets down to 1.2m width to fit a standard width LR3.
It will work, how much it will change, no idea really. HDPE machines very very well so if that is all you plan on doing go for it. It will just cost you some speed.
Another way to think about it is will any parts actually be that big?
I could use a full sheet build myself but choose to make a 1/4sheet machine for faster cuts in my size range. For my YZ plates a 1/4 sheet is still 6 sets with minimal waste and about an hour and twenty minutes of cut time. That is enough for me. I would not want to be stuck out here for 5 hours just to cut a full sheet…and I am not sure how much slower a full sheet would actually be compared to a 1.4 sheet machine.
You are not going to get black and white answers. Every choice has a tradeoff. I hope understanding the tradeoffs is a good answer for you.
