New to hobby - couple quick queries

Hello,
I am in the process of working out if a Shapeoko XXL is suitable for me, I intend to be batching out pieces in 18 & 12mm Soft and/or Birch Ply. As usual through Facebook I am getting mixed answers to my questions. I am using Autodesk Inventor to create my models & DXF’s as it is something I am fluent in and using Carbide Create to nest my parts.
Router to be used will be a DeWalt D26200.
I am looking for answers to the following:

  • While working with the above thickness’s what would be the suitable: stepover, depth per pass, feed rate and plunge rate for relatively clean edges, I will be sanding finished edges lightly to a smooth 1mm’ish radius so doesn’t need to be completely smooth. I am wanting to use 1/8" end mill to reduce waste.
  • while machining 2 parts side by side with tabs in between is it okay that when using a 1/8" endmill to have the space between the parts be just over the 1/8" essentially meaning when cutting out the 2nd part it wont be removing much material at all?
  • most parts being cut are roughly 100mm x 36mm with radius corners and smaller, this is what I am basing the value on the machine on. Image of small selection of parts.
  • also for a covered enclosure what should the internal height of it be to allow plenty of space for any cabling, gantry space and dust extraction? I am planning on building it into the lower shelf of an assembly bench with access on 3 sides, this will reduce the footprint as I will have more usable surface and also reduce the amount of sound coming from the machine, something I really need as I have 2 young children in the house.

Any help will be much appreciated, slightly simple answers will be helpful, at this moment in time I am not wanting to learn the full math re chipload etc but I just need to be able to justify the time saving, price and speed to myself. Also I’ve been wanting this for a while and want to learn a bit more prior to purchasing.

Thanks Guys
Dan

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You’re going to have a tradeoff of speed vs using a bit bigger endmill… a 1/4" will go faster (50 to 60 ipm easily) than an 1/8" (40 ipm typical)… especially with plywood (which is a bit irregular in structure) my instinct would be to try to go for a 1/4"… but if you go for 1/8" you need to decide if you want to use a straight cut bit or a “up and down” cut bit.

For 1/8" I’d use 45ipm, 0.045" DOC, 15ipm plunge

it’s ok to leave a bit more than 1/8" as you describe (rule of thumb: 10% minimum)… it’s ok to not always have full cutter engagement.

I built my enclosure nicely oversized and don’t regret that at all… more space for sure is more convenience… try to have at least 12" in the X and Y direction (6 on each side) extra… you won’t regret it. I made mine 3 foot high (but I have an XL. For an XXL I’d go 4.5 feet at least)… especially if you need to reach to the back of the machine, the more height the better… not just for the machine, but also for you as the human :slight_smile:

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I will note that it’s actually preferable to have at least 10% more than the width the endmill cuts in-between parts — you don’t want to cut a slot only as wide as the endmill and have 100% tooling engagement during more of the cut than is absolutely necessary.

For nesting, if you’ll be changing the parts cut frequently, have you looked into using automated software for this? See: https://wiki.shapeoko.com/index.php/CAM#Nesting

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Thanks for the replies. Arjun, your depth of 0.045" per pass seems very low? That’s almost 15 passes per piece. A lot of people online specifying 1x the diameter per depth. One gentleman showed 9mm depth per pass at 150 inches per minute for plywood cutting, this is ofcourse not something I believe or something I want to even attempt.
I was thinking 1/8" or so minimum per pass. What depth would be achieved with the 1/4" endmill? I was thinking of using upcut bits to pull all the chips out of the pieces. I would loose more material to the bit meaning less parts per sheet of plywood but if it is going to significantly increase the speed that I will get the parts out of the machine at then that will be more attractive.
Arjun, could you explain the difference between the depth of cut and plunge as in my British English these mean the same thing xD!
Thanks William, I will have a look a that as 90% of what I will be cutting will be nested parts for individual builds. Nesting simple enough with a history of nesting for water jet and plasma cutters.

you can certainly trade depth for speed…
(yes I tend to cut a bit conservative and go to 50% of diameter roughly)

if you go upcut, then you might want to do the very first layer a bit shallow, that way you get less splintering (plywood can be stubborn that way)

depth of cut == how deep the cut goes per layer
plunge rate == how fast the bit goes in the vertical direction

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btw generally folks start with relative conservative F&S and as you get comfortable with things you can crank it up… often 2x to 4x.

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I will be taking my time getting into it however I am also going to be needing to get the machine up to speed hence why I am looking at all of this prior to purchasing, will need the machine to pay for its floor space relatively quickly so I know it will be beneficial to me.
Through the first layer of ply I would be happy to cut at the 0.045" per pass for the first 2 but for the remainder I would like it to be a little faster from a production point of view.

if you want to go max speed, you might want to check the Pro model that comes out soon.

Some of the folks here manage crazy fast speeds even on aluminum … so much is possible

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The Pro here in the UK is going to be 2 or 3 times the price of the XXL due to modifications needed for British compliance

Hi Daniel, what modifications are you referring to ?

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I’m not 100% sure personally Julien, a retailer in England told me that when I asked if they would be stocking the new Pro XXL model.

If the price difference between the 3 XXL and the new PRO XXL arent going to be as big as they said then I would ofcourse consider the Pro

Anything along those lines is most likely speculation at this point in time — please check in at sales@carbide3d.com and we’ll do our best to research this and provide accurate information.

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Thank you William, do Carbide 3D ship internationally? I.e to Scotland. If so I would be more inclined to pay that extra bit on shipping to get it directly from the manufacturer in California.

Please check in at sales@carbide3d.com for the specifics of resellers and international sales.

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