1 Attachment(s)
New Build/First Time Build - BAM CNC
Hello everyone,
I am looking into building a CNC routing/millingmachine. I am fairly new to the idea buthave been researching a little about what to look for and other peoples “If Icould do things differently” notes. Please also note that I have not yet gotten into any calculation,yet. I am purely going off what I haveseen and researched.
THE DESIGN
- Try to keep costs low without sacrificing toomuch quality.
- Maintain a sturdy construction, especially forthe gantry.
- Able to cut a variety of materials includingwood, plastic, and some aluminum.
- Able to plug into a 120V socket.
- Able to be upgraded if needed.
- Replaceable parts
ELECTRONICS
Stepper Motors
- I decided to go with NEMA 23 motors afterreviewing NEMA 23 vs. NEMA 34. NEMA 34seemed to be a little overkill and a lot more costly.
- https://www.omc-stepperonline.com/cnc-kit/4-axis-cnc-router-kit-31nm439ozin-nema-24-stepper-motor-and-driver-4-dm542t-24hs34.html
Breakout Board
- https://www.omc-stepperonline.com/stepper-motor-driver/5-axis-cnc-breakout-board-interface-mach3-cnc-router-kit-st-v2.htmlSpindle
Spindle and Drive
- I decided on a 2.2kw air cooled spindle.
- I plan to purchase the common Chinese spindleand drive from eBay.
Other parts
- I was thinking that the E-Stop and limits I canfind for a good price on AutomationDirect.com
MECHANICAL PARTS
Frame
- I plan on using 8020 extruded aluminum. I plan on searching eBay for this portion. I also plan on having some 0.5” thickaluminum for additional custom parts.
Linear Motion
- Was looking into ball screws for the antibacklash and the precision.
- I am looking into using the linear slidescurrently, because they seem to be a lower cost without losing too muchquality. I wanted to use the Hiwinblocks and rails, but they are pretty pricy.
Please give me any insightabout the decisions I have made so far. I am an open book. Please add any helpful words you may have, helpfullinks, brainstorming ideas, and more. I plan on compiling all the informationfor this build to help others out as well.
One big issue I am runninginto when trying to keep costs low is finding parts and purchasing parts. I want to build the machine so that if a partfails I can replace it. I am trying tostick to standard parts or catalog parts (other than the spindle and drive,only because they are everywhere and can be replaceable). If anyone has good places to buy parts,please, please let me know.
Is going with lead screws initially a bad idea?
Is going with wood in place of the aluminum plates initiallya bad idea?
Does anyone have places they like to purchase partsfrom? Especially anything to do withball screws, lead screws, linear slides, and linear blocks.
Thank you for your help. I appreciate it.
Re: New Build/First Time Build - BAM CNC
Check this site for linear motion products. The link points directly to their version of Hiwin linear rails. overstock & surplus automation products: Linear Bearings/Rail, BLH Linear Guideway
I wouldnt recommend Mach 3 for your software. Consider UCCNC for control software and a compatible motion controller like the UC300 or UC400 series. I havent done price comparisons lately but I think it is less expensive than MACH3 and by all accounts better. I built my first router using a Gecko G540 driver and a USB100 controller from UCCNC. Pretty inexpensive components, and that machine was comparable to your design in overall size. That's another option.
If your considering ballscrews over rack and pinion due to backlash concerns dont. Each drive system has theirs pro's and con's but the backlash reputation that seems to haunt rack and pinion systems is pretty much non-existent these days. I used Moore Gear for my gear rack an 2 routers and neither had any backlash problems.
Good luck with your build.
Re: New Build/First Time Build - BAM CNC
Quote:
Originally Posted by
BAMIN
Hello everyone,
I am looking into building a CNC routing/millingmachine. I am fairly new to the idea buthave been researching a little about what to look for and other peoples “If Icould do things differently” notes. Please also note that I have not yet gotten into any calculation,yet. I am purely going off what I haveseen and researched.
In the end the important thing before designing your machine is understanding your expectations. Cheaper machines produce lower quality results and larger machines produce lower quality results when the same cash is put into them.
Quote:
THE DESIGN
- Try to keep costs low without sacrificing toomuch quality.
- Maintain a sturdy construction, especially forthe gantry.
- Able to cut a variety of materials includingwood, plastic, and some aluminum.
The above three work together to put your machine into a different Class than most initial builds, this especially depending upon what you mean by quality. Consider that in manyDIY machine designs the gantry is a weak point. Adding the desire to do aluminum (there is a wide array of what some aluminum means) means that you need a far stiffer machine if you have expectations for high quality machining in aluminum.
Quote:
- Able to plug into a 120V socket.
Generally this means that you have to limit spindle size or power that the spindle draws. This might not be a problem, it really depends upon what types of machining you ultimately want to do. The simple fact is that (in the USA anyways) most 120 VAC outlets are either 15 or 20 amps of current and for reliability you want to derate what your machine is designed to draw.
Quote:
- Able to be upgraded if needed.
If this is a real concern I'd strongly suggest making a more robust base frame from the start. If you don't you risk throwing out your entire machine because you can't get more performance out of a poor frame design. In the long run it is better to design a machine that has the functionality that meats your expectations.
Quote:
- Replaceable parts
I'm not sure what you mean here, if you bolt a part on you can bolt on a replacement.
I actually like AutomationDirect, we have used them from time to time at work and have always gotten good service. You do pay more but that isn't a big surprise.
As for the spindle, you can't reliably run a 2.2KW spindle from an 120 VAC outlet. This if you expect to draw full power from the spindle. Depending upon your goals it might pay to simply have a 220 VAC circuit installed.
Quote:
MECHANICAL PARTS
Frame
- I plan on using 8020 extruded aluminum. I plan on searching eBay for this portion. I also plan on having some 0.5” thickaluminum for additional custom parts.
I'm not a big fan of aluminum extrusions at all so my comments may seem biased to some people on this forum. T-Slotted extrusions can make for serviceable machines if they are sized properly and plenty of gusseting and angle brackets are used to make for a stiff frame. In any case I always suggest a steel beam for the gantry beam!
Quote:
Linear Motion
- Was looking into ball screws for the antibacklash and the precision.
You make no mention of machine size here but ball screws are certainly the better choice on smaller machines.
Quote:
- I am looking into using the linear slidescurrently, because they seem to be a lower cost without losing too muchquality. I wanted to use the Hiwinblocks and rails, but they are pretty pricy.
I have no idea what you are referencing here as to "linear slides".
The types of linear bearing you choose really depends upon budget and performance expectations. That being said linear rails can be one of the easier things to upgrade in the future.
Quote:
Please give me any insightabout the decisions I have made so far. I am an open book. Please add any helpful words you may have, helpfullinks, brainstorming ideas, and more. I plan on compiling all the informationfor this build to help others out as well.
You quoted a lot of stuff above but you said nothing about machine size. This is very important because it becomes very expensive to get high performance out of a large machine. Looking at your attached picture the frame of your machine just looks a little to spaghetti like.
Quote:
One big issue I am runninginto when trying to keep costs low is finding parts and purchasing parts. I want to build the machine so that if a partfails I can replace it. I am trying tostick to standard parts or catalog parts (other than the spindle and drive,only because they are everywhere and can be replaceable). If anyone has good places to buy parts,please, please let me know.
There are an endless number of supplier sitting on the net ready to supply our with parts. What passes as a good place depends upon what you are buying. Just to get started: Mc Master - Carr, AutomationDirect, Maryland Metrics, Travers, MSC, Jergens, 8020, Bosch, CarrLane, HEINRICH KIPP WERK, Halder, Del-Tron, PBC Linear, Pacific Bearing, Kenneth Crosby, THK, Techno isel, IGUS and many many others. Some of these vendors will refer you to local shops selling their product of services. Generally the local shops are small time operations that are focused on service.
Speaking of, your location is a significant factor in getting automation parts locally. If you are near a major city do look into what you can find for local automation suppliers. If you want to be buying standardized parts there is a whole industry built around supplying such. Often the local supplier won't be cheap but by the time you factor shipping and other expenses it may become a wash. Also don't forget that sometimes suitable local businesses or even national, may be discussed as something else. For example many of your local electrical contractor supply houses will have a line of supplies suitable for automation work. Likewise big national companies like Kaman ( a bearing supply house) have supplemental line of parts and components for machine tool building.
Quote:
Is going with lead screws initially a bad idea?
It depends upon machine size. At some point you have no choice but to go with rack and pinion. On smaller machines I would most certainly lean towards ball screws / lead screws.
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Is going with wood in place of the aluminum plates initiallya bad idea?
If you want to do aluminum, wood machine parts are a very bad idea. This due to the need to use a lubricant/coolant. If you aren't going to be doing aluminum to any extent, there are many successful all wood machines out there. As your desire for high quality increases, with respect to aluminum machining, the less desirable that wood and even extruded aluminum becomes.
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Does anyone have places they like to purchase partsfrom? Especially anything to do withball screws, lead screws, linear slides, and linear blocks.
Didn't you just ask this question? I'm assuming you are familiar with Amazon and E-Bay.
Quote:
Thank you for your help. I appreciate it.
Remember it is all about your expectations. Nail that issue and your design just follows based on your needs.
