I just recently got my Maslow CNC kit in and I am extremely excited with the potential that this kit has to offer, the amount of customization that you can apply to it, and the community backing it.
I have been doing a lot of reading on this site prior to building my frame so I can try to capture as many lessons learned as possible, but I want to make sure I do not miss anything major/important.
This is my current plan for the frame:
- 12’ 8020 Beam for the header (reduces deflection, able to adder roller to guide cables)
- Unitstrut rails to make up the rest of the frame (1/2 Height slotted hole)
- Ability to adjust distance between motors (Accuracy tuning)
- Ability to adjust distance between work plane and motors (acommodate different material thicknesses to keep the chain planar)
- 3D Printed chain guides to keep chains engaged on gears, and to lock in place when not in use
For the sled:
- Replace bricks with cylindrical containers that hold lead shot (or diving weights)
- Round edges to reduce chattering of the sled
- Connect shop-vac hose to reduce sawdust
For Design:
- Using Siemens NX 11 to create G-Code
- Need to ensure linear coding is used not parametric
There are still a few things I could use help with, but I might tackle these after the frame is built:
- Cable Tension (How to improve tension in the corners to increase accuracy)
- Improved Z-Axis control methods for the sled
- Configuration of spoil board / excess
Let me know if you think I have the full scope covered, or if there are some other things that I should be considering. Also if you have a particular forum post you think helped you greatest, feel free to share.
Simplest way to increase tension in bottom corners is to add weight to the sled. Using the spreadsheet looks like a 26.75 lb sled is about as heavy as you would want to go. with a 12’ wide motor distance that will give you about double the force in bottom corners vs stock design which was never good in corners. https://docs.google.com/spreadsheets/d/1gJ0pFBTLs5e8DpaqLpfbvMJVMYtIeOf9lCrewq1Zg-c/edit?usp=sharing
I haven’t noticed anyone doing that. I didn’t think this was necessary. Fix the motors so everything is rigid and adjust the settings in the software for accuracy tuning.
This is my current plan for the frame:
- 12’ 8020 Beam for the header (reduces deflection, able to adder roller to guide cables)
what dimension beam are you looking at using? unistrut is 40mm and it seems to
flex a bit, if you are using 80mmx20mm that may or may not be rigid enough.
- Unitstrut rails to make up the rest of the frame (1/2 Height slotted hole)
- Ability to adjust distance between motors (Accuracy tuning)
as others have noted, no need to move the motors, just change the setting in
software.
- Ability to adjust distance between work plane and motors (acommodate different material thicknesses to keep the chain planar)
- 3D Printed chain guides to keep chains engaged on gears, and to lock in place when not in use
I don’t think this is needed if you have the motors at the right distance so
that the chains are parallel (both sled side and slack side)
For the sled:
- Connect shop-vac hose to reduce sawdust
note that a shop-vac is about the noisiest option for dust collection (likely to
be as loud or louder than the router), and you want to make sure the hose isn’t
pulling on the sled (or preventing the sled from going all the way down)
For Design:
- Using Siemens NX 11 to create P-Code
- Need to ensure linear coding is used not parametric
I am using the 80/20 fractional 15 series beam so it is 1.5” x 1.5”. The website has a handy deflection analysis tool which shows deflections well under 0.100”. As for the Unistrut I was looking at Superstrut which is carried at most home improvement retailers and it comes in 1 5/8” x 1 5/8” (which is the 40 mm standard). If I went that route I would be putting cross members in. I am open to other suggestions as well.
I guess I need to look into some of the tensioning diagrams again. If you change the thickness of the material you are milling what adjustments do you need to make?
One problem you may have with that softare is getting it to create primitive
enough g-code for the maslow. you will have to look at it’s settings to see if
you can tell it to make g-code for grbl or what it’s config is to define what
g-code a machine understands.
I have to find the post but I remember someone bringing this up in regards to NX 12. The main thing is to try to figure out how to get it to generate linear curves instead of parametric. I will dig around into it a bit more.
Yes, pulleys are used with bungees or weights. Search “chain slack management” and you will find a lot of examples. On my frame post you can see what I did.
@ThatAirplaneGuy
Edit: added link to the topic I created for my frame build that shows how I manage chain slack.
I saw that and I can tell you that there must be a lot of assumptions behind that number, which I have not seen. My experience is that it twists and bends very easily if not very well supported along the length of the strut.
Yeah the main thing I will need to do is replicate fixed supports using angle brackets. I think I am also going to be using three vertical members along the span instead of two and/or some diagonals to give it more stability. Thankfully I am a structural engineer so it should be pretty straight forward (once I get time to sit down and do it haha)
sorry about that.