Since we may be contracting 3rd party to make PCBs and supply parts for the CNC, I'd like to gauge how much real interest there is in buying one of these machines, when we're done.
Keep in mind that this is not a commitment, just think to yourself to see how serious you would be, and comment yay or nay.
Update June 8th, 20122:
Ok, just counting heads. So far it's 17 people. Let me know if I missed anyone.
My personal budget for this is $1000-$1200, so any higher, and I'm out, but of course would continue to do my best to get this done for everyone!
Here's a list of "yays" so far (again no commitment assumed):
Drive System Survey
Franco Scipioni has set up a survey to gauge interest in which system we want to have on the system.
Access the survey here:
- has rotational encoders to allow exact motor control
- position encoders, so that tool head can be positioned precisely
- uses DC motors
- requires development or use of a custom circuit board to drive the motors
- more expensive solution
- no rotational encoders, so will not allow exact motor control
- position encoders, may still be possible
- uses stepper motors
- no custom circuit boards needed, motor systems easily available
- cheaper than servo system
This looks interesting and versatile.
Smoothie is a free, opensource, high performance and modular G-code interpreter and CNC controller for the LPC17xx micro-controller ( ARM Cortex M3 architecture ). It currently runs on mBeds, LPCXpressos, SmoothieBoards and SimpleCortexes. Porting is ongoing to 4pi ( SAM3U ) and STM32F4. The motion control part is a port of the awesome grbl. The Source code is on GitHub
General guides for Smoothie and Smoothieboard on different machines
This looks interesting and versatile.
I have a Shark HD CNC machine and I am looking to try to add a 3d print head to utilize the X, Y, Z positioning. I am interested in your post, too.
Can I put my hand up for this please?
It looks like this maybe 12 months old but you guys are still working on it.
Hi All, new to the group and have just read the history. Sounds great.
I'm based is Aus so a little challenge but happy to help where I can as I have a long background in electronic construction and design from my defence days. Put me down as yes. Looking at the servo version for me I think.
Hi Everyone, I'm In.
Happy to help in anyway I can.
I have a software background.
Here are the poll results and responses as of today. It's quite interesting that its 50:50 at this point. For the most part, most of the reasons for choosing one or the other have to do with price, accuracy, power, and other reasons that have already been discussed, but there are some that are less obvious and It's cool to get these responses and see different perspectives. Unfortunately, it looks like this poll is inconclusive thus far :( If there are more responses I'll post them too :)
Poll Results as of 8/9/12 @ 3pm ET
Stepper Motors: 39.1% with 9 votes
Servos: 39.1% with 9 votes
Another Solution: 21.7% with 5 votes
1. Servo controller with a stepper motor (ex. QuickSilver Controls)
Reasoning: Best of both worlds... lower cost compared to straight up servos, yet with similar performance.
2. either ,but want encoders
Reasoning: want feed back in machine. repeatable positioning. dont want to have to find zero point if power is lost or machine overloads and trips circuits.
3. I'm too ignorant to have an opinion! (lol)
Reasoning:but if the cost difference is "not too much" I would prefer the higher quality option.
4. Servos with Positional Encoders
5. Depends on users needs
Reasoning:Either will work fine but depends on the user budget and what the user hopes to do with the machine. Build the mechanics of the machine first. Then determine the forces needed to move the parts. Then determine the forces needed to cut the desired materials.
Reasons for choosing Stepper Motors:
1. A printer can place a small dot of ink on a page with reproduced accuracy, using steppers and opto feedback (simple disc) and it is the cheapest, why use servo's?
2. Price. Just need upgrade ability to servos in the future.
3. Servos aren't precise enough to correctly control velocities of the various CNC axis
4. Lead time, it's off the shelf. Ultimately I want servos but I'd rather have a machine than wait years
5. I am doing light work with wood an aluminium.
Reasons for choosing Servos:
1. Quality over price
2. Much more Power
3. more power and precision, looking for pro grade CNC
5. Servo Feedback with encoders provides better reliability. Machining can be both accurate and precise allowing for more exact replication of models. In woodwork designs (and other projects), multiple products can be made with more certainty that they will all come out the same.
6. closed loop vs open loop. I know that this would be pricey..
7. more experience with them
Ok folks I added the survey link and my description of what the servo vs stepper system is up top of the discussion. Monroe, and RD, please correct or add any info you wish up there for everyone to see.
Here's the link again to the survey created by Franco:
Here is a quick survey for gauging interest on steppers vs servos for the prototype. You can state why you chose that, define a specific stepper or servo, or just add any comment you want. It should display results after you vote and I'll post the "why did you choose this" comments after a number of people have responded.
Click here for stepper vs servo!
I'm in as well :) - I've played with some small cnc stuff, but haven't completed my first build yet, so this would be a great one to get in on..