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Zenbot 4848

Circleville Signs

Circleville Signs

New Member
Well, after kicking it around for a year or more I think I am going to order an entry level CNC this week. I had pretty much settled on the Carvewright, even thgh many don't like it's limitations. I was ok with them as I have seen some SICK work come out of them. That said, the size limitations got me looking around again and I stumbled onto this: www.zenbotcnc.com

Now I am super intruiged. Wondering if anyone has knowledge of this machine? It uses timing belts rather than lead screws, and for the price, I figure the worst case I have a solid learning machine. For less than $3k I can have software, router, and dust collection...


Thoughts?
 
rjssigns

rjssigns

Active Member
First off I don't know that much about CNC equipment. Although I did spend a large part of my life building precision equipment. I'd be leery of belt drive. It will not have nor maintain positional accuracy. At some point you will want to do push through letters or similar products and you won't be able to.

I am in the process of gathering parts for a custom build. My brother is doing the engineering. I tried doing the math and it made my head hurt. Our CNC will be made from billet aluminum parts and some extrusions. Axes will ride on linear rails/bearings. Drive will be ball screw with steppers initially. When done it will be able to machine aluminum.
 
Circleville Signs

Circleville Signs

New Member
That is my biggest concern as well. I'm really hoping Artbot can chime in here. The belts are SERIOUSLY heavy duty (Kevlar reinforced), and 3/8" thick. Being belt driven makes this thing ridiculously fast - and I don't plan on using it as an automated jigsaw - more for creative, 3d purposes.
 
FatCat

FatCat

New Member
Definitely looks cool, and a low cost solution for those wanting to enter this type of market. However, I too have concerns about accuracy - but I wonder if it would be "good enough" for use on soft materials like PVC, HDU, etc?
 
rjssigns

rjssigns

Active Member
FatCat said:
Definitely looks cool, and a low cost solution for those wanting to enter this type of market. However, I too have concerns about accuracy - but I wonder if it would be "good enough" for use on soft materials like PVC, HDU, etc?
Click to expand...
Click to expand...

If you read the details(which are very spare) they are alluding to it being a light duty rig. I would however have no problem using that platform to run a plasma cutter. Should work very well. Belt set-ups are great for things that do not "load" the belts/drives.

You will also notice they do not have any specs on positional accuracy, repeatability, backlash or belt stretch compensation.

Not meaning to wet on your picnic charcoal, but I wouldn't expect too much.
 
artbot

artbot

New Member
any cnc, the worst most accurate cnc is better than "no cnc". i'd get an old school shopbot if i was getting into the cnc game. huge user support on http://www.talkshopbot.com/forum/, i've been able to fix my ancient one here and there with minimal technical skill. if you can pick up a used cnc 4x8 for around $5-7k you'll have a working cutting machine and on certain projects have a pricing advantage.

http://www.ebay.com/itm/Shopbot-CNC-Router-/111029822025?pt=LH_DefaultDomain_0&hash=item19d9e4a249

[url]http://www.youtube.com/watch?v=JvhNgNk4f24&feature=youtu.be
[/URL]
 
Circleville Signs

Circleville Signs

New Member
I agree that I'd love to have a 'Bot - however $5-7k is roughly 2-3x my budget...lol

I just got off the phone with Shaun at ZenBot....Pretty cool guy. Here is what I was told.

1. Accuracy to .001, with resolution to .0005. Resolution marks show up more than actual mill marks!

2. I asked him directly about the belts, and my concerns about backlash, etc. He says that the backlash is less than with lower end lead screws. More importantly, in 5 years of making the machines, he has yet to have a customer need to replace the belts - and some of his customers have serious heavy workloads.

3. He is developing a 4'x8' machine as well, so if I get this and like it, I would have the option to updgrade to a larger machine without having to relearn the system.

I told him that I very well might be calling back with more questions - any ideas of what else I should be asking? I'm a total NOOB on this stuff.

 
artbot

artbot

New Member
i'd go for it. you'll be able to come up with lots of of work arounds from cutting one letter at at time, to feeding panels through with tables on each side. 4' wide anything will not be terribly limiting. as for accuracy... it's a sign, not a machined part or a cabinet. just cut the damn thing and leave your tape measure out of it.
 
4R Graphics

4R Graphics

New Member
I have experience with CNC machines both hobby level and DIY (I have built a few of them)
Timing belts are fine they work great the big draw back to them is that if your machine is built heavy duty then you must start slow ramp up to speed and ramp down to stops.

You can make them really fly though on large machines 1800 inches a min no problem.

If you know that you are going to use this machine for light duty such as signs and very light aluminum then go for it the belt drives will be fine.

If you want to machine aluminum block well then you will need to go to either ball screws or rack and pinion drives.

Dont even think about steel if you get a machine heavy enough at the hobby level it may cut it but it will be very slow and the cuts will be crap (theres a reason why mills are built from cast iron).

Also there is the question of precision do you need it to be accurate and repeatable by .001" belt drives can do this if the machine is built right.

For Sign work in foam, wood, acrylic, plastic and light aluminum most any cnc will work just pay attention to the accuracy and the repeatability they are the key also most companies will say rapids at 1800" min thats great but all that means is when the machine moves from one place to the other (not while cutting) it will move at 1800" min most of the time you will machine at a fraction of that speed (wood foam etc.. roughlly 100 to 400 ipm) aluminum 100 or less ipm.

Just my 2 cents.
PM me if you want more info I have enough to make your brain hurt.

Edit
Just went and looked at the machine should be capable if you dont do anything hard like aluminum (aluminum sheet like max metal would be ok).

You also have to buy with that the Gecko drive (love those things) the mach software (it reads the code and tells the motors what to do) Cam software (takes your design and makes g-code ie tool paths) so your looking at a ball park of $800 plus the cost of the machine to be able to use it.

Personal note I would buy a 4'X8' cut area machine you will regret it if you dont (unless you have a specific use for the smaller machine).
 
R

RAP&F

New Member
cnc cutting

We just purchased a CET flatbed 4' x 8' with plans to farm out any cnc cutting in the short term. I've always assumed that cnc equipment would be a $100,000 investment down the road. If all I really want to do is basic cutting on the standard substrates (foam core, various corrugated materials etc), could a $3,000 system like this be a viable solution? How about one of the $15,000 machines like a Laguna tools Swift cnc? Basically I just need to cut basic shapes following a die line, I don't expect to do any carving or metal cutting. I appreciate any input.
 
F

fixtureman

New Member
Circleville Signs said:
That is my biggest concern as well. I'm really hoping Artbot can chime in here. The belts are SERIOUSLY heavy duty (Kevlar reinforced), and 3/8" thick. Being belt driven makes this thing ridiculously fast - and I don't plan on using it as an automated jigsaw - more for creative, 3d purposes.
Click to expand...

When you say fast how fast is it? As for a plasma cutter it is plastic and I think the heat would warp or melt the parts it is made from. Light duty is about right and belts on a router is not a very good idea when the forces to cut get a little hard. Belts on a laser cutter is ok because there is no real force on the steppers.
 
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