I’ve been kicking around a concept in my head and wanted to toss it out for consideration.
Rather than trying to make the existing Maslow concept do everything, what if some of the most innovative aspects of the Maslow were mated to some of the best CNC concepts from the gantry world?
Use the Maslow style concept to accurately move a small ridgid CNC router, like say a 12" x 12" gantry style “sled” around the 4x8 sheet, but do all the cutting on the very small and rigid traditional machine. (Maybe even 6"x6"?) So you get the vertical model/small footprint (for a 4x8 capable machine), you get the big work area but you could also potentially get excellent rigidity and accuracy from the more traditional CNC sled.
As another upside, the slower repositioning of the sled by the maslow can be offset by more rapid feeds and speeds once you reach the target area and start the cut. Of course the big question becomes, how do you stabilize the sled, but perhaps the 4 motor maslow is the answer there?
I’m just blue-skying here. But I’m guessing making a rigid gantry at a small enough footprint can be done quite easily and inexpensively compared to running over large distances?
Anyway, lots of elements to discuss and consider, I just wanted to throw it out there as it was an off-the-wall idea that was percolating and I thought it was worth sharing.
the accuracy issues with the maslow are due to the two-motor angled drive.
Anything that keeps that is going to suffer the same accuracy problems, adding a
gantry won’t help (in fact, the problem of the gantry racking under the uneven
drive forces could cause more problems)
the maslow speed can be increased significantly by using bigger motors and more
poweful drive chips, but that’s a cost thing (it may be that there is room for a
cheap, $500 maslow, and a faster $1000 maslow, but time will have to tell on
that)
size does make a difference in the difficulty of making things accurate, the
error you get from the clearances in the chain are much more significant when
you are talking 500 links (~3000mm) vs 50 links (300mm)
I don’t understand what you mean by a ‘gantry style sled’ to move around the
sheet.
I wouldn’t totally dismiss the idea of attaching a small open bottom gantry system to the Maslow. But I would see it more as a fancy attachment/upgrade to an existing system. Let’s say you want to have intricate details on a large piece. You could us a vacuum system (maybe) to suction stabilize it on the work piece using a relay to turn it on and off. Then for the real cutting you hook your original sled up again. Or you just have the gantry system lock into a fixed 0,0,0 position.
Ass for the a more expensive 1000 dollar Maslow. That could also be an upgrade. While I think it is laudable to have a sub $500 system, the biggest investment is in the time to build the scaffolding, and a good router/spindle. A much faster system will eventually pay for itself…
The idea of having the hobbyist start with a $500 entry system who is then able to upgrade his system to do work faster is I think the way to go. The question is, how much faster can you really go with this design?
the main limitation of cutting speed is the amount of force available from
gravity to move the sled (along with the friction of the sled)
shifting to a gantry style machine where the motors can apply force in all
directions would let you cut much faster, but would be a very different machine.
As far as I understand it, your main objection to a gantry style machine is cost. If you used the classic Maslow machine to cut the frame for a gantry style machine, and then upgrade the motors, belts, etc…but still recycle as many parts from the original Maslow. Wouldn’t that achieve your goals as well? Because even a gantry style CNC machine could be mounted vertically and still work if space is an issue. Or maybe mounted like a Murphy bed to the wall
$430 maslow kit
$100 wood for frame
$170 ridgid router
total of $700 assuming you have a cheap pc already to run the software.
Maslow has never been sub $500 kit.
the heaviest sled that can be used safely with the current kit is about 30 lbs. and even that requires a pretty tall top beam about 30-40" tall to keep center forces manageable.
I would assume all things being equal that going from a 20 to 30 lb sled would mean 33% faster.
so for a 4 hr job (240min) it would now only take about 160min.
seem like one would need a speed increase of at least 2x to seem impressive enough to pay for the faster speeds and I do not think that is possible with current motors.
just going from a 10’ top beam to a 12’ top beam can increase the minimum force
(and therefore speed supported by gravity) by 2x, without increasing the sled
weight.
but the current motors have a theoretical limit of about 48 ipm, and the other
problem is that the firmware doesn’t do any acceleration planning, it assumes
you go from stop to full speed in an instant (and that you stop just as fast)
so going to a heavier sled doesn’t gain you nearly as much as a wider top beam.
so you quickly get to where you need faster, more powerful motors, which will
require a beefier motor controller board…
So David, I am sure that you looked into stronger motors, in your opinion how much more would they be? I think the controller boards would not be that much more component cost wise.
if you want to make the maslow faster there are 2 simple things to try first #1. use bigger motor chain gears. the stock are 10t , I bought some 13T, but have yet to test it, zero other people have tested this too. There are a lot of ideas on this forum but only a small percentage of people actually take the time to try something new. This is the no brainer first step IMHO.
above thread also answers your question on the motor size, they are about $10 more each so $20 more for two bigger motors, but no one has tested them and I do not think they use a worm gear so might be an issue when turned on and off if chains slip.
it depends so much on the motors that it’s hard to tell.
People have made better motor controllers, and the jump from the stock one is
significant (from ~$20 to ~$75 or so)
like so many maslow components, everything is ‘just good enough’ and just below
the threshold of a significant price jump.
Now, the one thing that could be done easily and cheaply is to get the 24v
versions of the motors. I don’t know ho much modification the motor controller
would need.
watch the max force needed (make the top bar higher than stock) so that you
don’t run out of force along the top. If you do, the common symptom is that a
cut along the top will droop and then hook up at the end.
You are right…there are a lot of people with opinions and not enough actions…I am one of them I guess. I am in the middle of building my first try at the Maslow. Once I have the basics working, I will start to tinker.
Just as an aside, and without me having to go through the spreadsheet, how high above the working area should my motors be for optimum speed and accuracy?
the higher the better. most ceilings are only 8 ft tall and that means the max height is limited to about 30-35". The motor bar should be 12’ long if you plan on cutting the full 4x8 at once, otherwise just cut in the middle. most projects do not use the entire 4x8 anyways.
30" tall by 12’ wide is a good compromise. The numbers do get better with 16’ motor bar, but most do not have the space and even if they did, how often do they really cut 8’ long pieces???
It’s a matter of trade-offs, I heard someone say they were going to build a
machine with a 14’ wide top beam that was going to be about 9’ tall, I don’t
think they reported the results yet.
