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  • Corner Folds on CNC, advice and guidance please?

    Posted by Jamie Palmer on May 8, 2021 at 7:11 pm

    Hi All, I have recently got a Yeti / Trend SmartBench and had some good results on cutting 3mm ACM letters, acrylic etc. I have been trying to create a Tray sign and having some difficulties with the folded corners. The 4 grooves are being cut first with a V-groove bit with a flat 3mm bottom (creates a nice clean fold line). Then 6mm Aluminium single flute around the external shape cutting in 4x 90degree triangles for the folds. The issue I am having is the fold is very tight and pushes out the folded section. I have manually adjusted the cut to try and allow some space but its just not getting the desired result. I am cutting the path on the outside of the line. Any advise or guidance would be great. Thanks

    Jamie Palmer replied 2 years, 9 months ago 4 Members · 8 Replies
  • 8 Replies
  • Phill Fenton

    Member
    May 9, 2021 at 4:11 pm

    I’m assuming you’re compensation for the width of the cutting flute? That being the case then the only other thing I can think of is the cut on the 90 degree triangles will have 6mm rounded corners instead of sharp corners. I always cut mine using a jigsaw so the corners are sharp. Perhaps you need to file the rounded corners away to create a sharp point to enable a cleaner fold?

    • Jamie Palmer

      Member
      May 10, 2021 at 8:11 pm

      Hi Phill, thanks for the reply, the corners are ok as Vcarve allows you to select the corner to be sharp rather than rounded as of the bit. The Cut Out being a 90degree then has the option of being cut on the line (using a 6mm bit – 3mm either side) or opting for and outside cut which then calculates the bit position to have the full 6mm outside of the line. I have almost run out of offcuts trying to get this! I imagine its really straight forward once you have figured it out! I will update my findings here for anyone else when i get it.

  • Kevin Mahoney

    Member
    June 15, 2021 at 10:11 am

    Hi Jamie, how are you getting on with your new machine? I’m unable to get a demo on the machine in the current state of affairs & I’d be interested to know if it has any drawbacks to a conventional cnc

  • Jamie Palmer

    Member
    June 15, 2021 at 12:08 pm

    Hi Kevin, yes it seems to exceed expectations every day! It’s current limitation is me operating it! Two friends of mine have viewed it and are putting orders in. Really nice finish on the dibond, acrylic cuts nice although only been upto 3mm so far as that’s all I have needed. I would be more than happy to let you drop by and take a look if that will help you? In terms of relating it to conventional Cnc machine which doesn’t have tool change facility I would relate them on par. The main limitation with Cnc’s are the bits and spindle. The spindle on this system is removable in literally 30seconds so I plan to order a second (+£700ish) so if it’s being worked hard continuously I can give the spindle a break. I shaped an 8ft panel this morning with cut outs to clad a security gate and it cut out in 3mins. I could not snap a piece of dibond in that time scoring it with the javelin. It’s also super quiet compared to the normal Cnc’s you can have a conversation with someone whilst it’s running standing next to it. If anyone has any questions feel free to ask. Please note I am not affiliated with yeti or trend in anyway, this is simply experience I have had whilst making signs.

    Side note if you currently buy Cnc bits in, bear in mind the resources needed, bits, glues, tapes etc and time when comparing cost etc. It’s not a whole lot of difference I just went this way as I like to have the control and speed afforded by owning one. Thanks

    • Kevin Mahoney

      Member
      June 15, 2021 at 8:40 pm

      Wouldn’t mind having a look at that going if you don’t mind mate, will message you to see if it’s convenient when I can sneak off for an hour, I don’t think I’m too far from you

  • Jamie Palmer

    Member
    June 15, 2021 at 8:55 pm

    Not a problem or happy to FaceTime you if you can’t be freed!

  • Simon Worrall

    Member
    June 16, 2021 at 10:50 am

    I may have got this all wrong but how do you get a sharp inside corner with a 6mm bit?
    Like Phill says, it must end up with a radius, that interferes with the fold. He does it with a jigsaw. I do it with a 3mm bit, which even then pushes the corner out slightly when you fold it, but not enough to be a problem.

  • Jamie Palmer

    Member
    June 16, 2021 at 9:06 pm

    A normal 6mm bit will do the job fine, it’s in the cut path setup the external cut of the tray needs to be set to cut outside the line. This means that when it cuts out the fold it’s allowing for the line and cutting to it rather than along it which would result in loosing half the width of the bit either side of the line. This then means you end up with a small amount of rounding right in the corner but on the outside of the line. This is also in the part that is grooved so is easy to sharpen with a blade or square file to get perfection. I hope that helps, it has taken a bit of head scratching for me but works well. If you want to post your g code I am happy to take a look if your using Cnc. Thanks

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