Planning For Next Season (2): Buying a CNC and Being Cost Effective

As we rode back to the school on our bus from the State competition, Danny and I discussed some of the changes we need to make by next season. One of the top issues on his list was getting either a 3D printer or a CNC machine so that we could create custom pieces by ourselves without having to get things done over at Rockwell or Intermec. As I may have mentioned in a previous post, we actually had an issue regarding Intermec and our rack and pinion system, which was reliant on a piece they helped us mill. When we needed to make two copies of the original piece (one to replace the existing and the other to create a second system) the machinist there did not want to help us because some of their tools had gotten broken during the original mill. While I understand where he was coming from, this still set us back a good deal of time and money to order the Tetrix rack and pinion. We hope to avoid these issues in the upcoming season with the use of a CNC machine.
because most of the pieces we use on the robot are made of aluminum, Danny and I have decided that it will better suit the needs of the teams to buy a really nice CNC machine and wait to buy the 3D printer until later, as opposed to trying to buy both this year. Doing this will also help us to keep our work area relatively clear. Right now we are still sharing our room with the AEA associates (who have been very friendly and pleasant in the past few months) and keeping our workstations clear and free of excess clutter is not an easy task. So only having one new machine to worry about is preferable to having two.
Jerry has mentioned that we may be able to cut down on our spending next year by buying aluminum blocks and sheets and milling our own Tetrix equivalent pieces. although the amount we will be saving will likely not match or even come close to the cost of the CNC machine, it’s certainly a start and it couldn’t hurt to try it (if nothing else, just to see if we could). Another jerry inspired thought was that concept of making our own CNC machine. As the average YouTuber can quickly discover, this idea is not entirely unheard of and actually fairly practical… if you know what you’re doing.

The alternative option would be to buy a CNC that’s ready to go out of the box or a DIY kit like this one from Inventables.

Personally I feel like it would be a better use of our time and that we would end up with a better product by buying a CNC or a CNC kit. I actually feel that buying a kit wouldn’t be a terrible idea – not only because it would save us some money – but it would also help us to better understand how the machine works.
We clearly have some research to do before we decide, but this is one goal that we must deal with before school starts in August.

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5 thoughts on “Planning For Next Season (2): Buying a CNC and Being Cost Effective

  1. Hey man, tell me how the Shapeoko CNC machine works out for you! I was looking at it, but have not bought it because I’m somewhat doubting its ability to easily cut think aluminum. Instead, I’m using a shopbot at a local fabrication lab. Anyways, I would love to hear how it works out for you and which shapeoko version you’re buying! (also any accessories like the acme z-axis upgrade and such)

  2. Hey Noah, thanks for commenting! I’ll be sure to let you know if we have success with that, but it may be awhile before we get one. We’re very low on funds right now, and with our coach leaving the school district for another job, we don’t have the ability to fundraise easily (district policy). But I’m fairly certain that our woodshop teacher has one that he uses for carving and engraving, and we have thought about asking him to borrow it. Just out of curiosity, what’s your reasoning for thinking that the Shapeoko wouldn’t be able to cut thicker aluminum? I suppose it depends on what you mean by thick, but for our purposes, I think the Shapeoko would probably be fine. I’m guessing a metal bit (CNC bit for metal, not wood) would help in the process. And if I’m not mistaken, I believe you can control how much material is taken away each time the bit passes over (correct me if I’m wrong, I’m basing this off of websites and YouTube videos). So if you were concerned that the Shapeoko wasn’t going to be able to cut the aluminum, you might be able to work around this by having the machine work slower, take off little by little, and by having a decent bit attached. Sorry if I sound like I’m making a sales pitch for this CNC, I’m just loving that low price. Like I said above, our team has money issues, so the shopbots are completely out of the question. For now, any custom pieces we may need will have to be made at Rockwell Collins. Oh, and just as an additional note, what would this “z-axis” upgrade do? Does the Shapeoko not have the ability to control the depth it cuts at? I’m assuming that’s what is meant by z-axis.

  3. You’re completely right, the Shapeoko can take off the metal layer by layer like any other 3-axis CNC machine. However, I just worry about how it holds up. When I saw videos of people cutting aluminum, they were adding machining oil before every path cut, and it seemed to take quite a bit of time to cut a small, simple part. The parts that I’m machining are very complicated, such as this part, and I just want to make them in a timely manner. Ultimately, I would like to hear about how it works out for you, and then I will decide wether or not to invest in an in-house CNC machine.
    The acme z-axis upgrade kit just replaces the belt-driven z-axis on the original Shapeoko. The Shapeoko 2 comes with an acme driven z-axis built in. Both Shapeokos and every 3-axis CNC machine can control at which depth it cuts.
    Have a good day, and tell me how it goes!

    • Oh ok, that makes sense. I suppose if the whole point of the CNC is to have an automated machining tool, then it would not make much sense to have someone standing there, adding oil at every pass. I’ll let you know how it works for us over the summer. You have a good day as well!

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