The gantry CG is closer to the front Y bearings but it is still between the front and back bearings. The image below is from an earlier version of the CNC, I am in the middle of fine tuning the CAD model so I am unable to make an updated calculation of the CG, but it should be similar to the attached image, maybe a little further back (to the left). After the cables are added, which will be attached to the back face of the gantry, the CG will move even further back, so it will end up being closer to the middle of the front and back Y bearings. However, the location of the CG is not that critical as long as the linear guides are able to handle rotational loads. I am planning to use square profile rails which a rated equally for forces in any directions.
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I’m glad you understood my explanation. Thank you for subscribing, this project will take some time to finish. Hopefully I will very soon be able to post some real life progress beyond the CAD drawings. Hope you enjoy journey.Everything is clear , I am subscribed and ready to see the progress!
Thank you John. That is a CNC mill. The photo is taken through one of the viewing windows. While it is operating, there is ALOT of cutting fluid being directed to the cutter and it flies everywhere!YEAH!! You started working on Carlos!!
Is that a manual or automated mill at your brothers shop?
Congratulations!! This is going to be epic!
Thank you NickNice!
Carlos is destined to be "very worthy". Congrats on the official start of your build!
Well, Carlos has evolved considerably from the machine he started out to be. The problem with making a minor adjustment here and a little tweak there is that before you know it, you have rebuilt the entire machine from the ground up. This what Carlos looks like right now:
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I moved the motors so they sit inside the envelope of the frame to try and save a little space. Carlos has grown to a size that is pushing the limits of the available space in my garage so by relocating the motors I was able to recover some of that valuable space. Of course, with the new location of the motors, they are unable to directly drive the ballscrews so a short timing belt and pulleys were introduced into the design. The image below is one of the Y-axis drives,
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And the next two images are the X-axis drive. The second image has a 3D pri yes cover to protect the belt and also to protect any carelessly placed fingers from being eaten by the machine.
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I really liked the way the belt drives turned out but I am now running into issues with actually sourcing suitable belts and pulleys. A disadvantage with living on the other side of the world from all major industrial suppliers is that we don’t have access to all the items in a manufacturer’s catalogue so sourcing parts is either not possible or very expensive. This has made me take a break to rethink some of the design. I could persevere with the belt drives until I find the right parts or I can slightly shrink the size of the machine and move the motors back to the outside of the frame and direct drive the screws. Decisions, decisions!!!
So to give my brain a break from Carlos, I started modelling the first guitar project for Carlos after he is built. It is a Spector NS-2. @John Nicholas first introduced me to this beautiful bass guitar in one of his threads and I fell in love with it right away. I might also add that John is also responsible for inspiring me to build my own CNC machine after seeing the amazing work he is doing with his CNC build.
Those of you who know me know that I don’t know how to play so I am choosing to build instruments purely based on aesthetics. One of the members over at TalkBass was kind enough to make some lovely drawings of the Spector which I loaded into fusion 360 to create a 3D model. This is where the model is up to so far. Still a long way to go but it looks enough like a guitar to justify making a few rendered images.
The first two images are maple body and neck with walnut fretboard.
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These next images are using metal materials because they are shiny
First one is a bronze body with maple fretboard
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And this one is platinum body with carbon fibre fretboard. If I remember, I’ll have a look at the estimated weight (according to fusion) of these solid metal guitars. I imagine they would be VERRRRY heavy, but it’s bit about being realistic, it’s all about a pretty, shiny object.
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I hope to have Carlos all finalised very soon, I can’t wait to make a proper start on the construction. The two little parts I made at my brother’s shop were just a teaser so I can say that some real parts have been made outside of the CAD universe.
Have a wonderful day/evening everyone.
Yes my ratio is 1:1 since the machine is made for milling wood and soft metal,like aluminium etc, also the gantry of the cnc is going to weigh about 45 kilos.Hi Nick,
Saving space was the main reason I decided to use belts and pulleys. Do you use a 1:1 drive ratio on your machine or some other ratio?
The motors and ballscrew ends that I'm planning to use both have a 10mm shaft, so they can use the same size bore on the pulley. Most of the local suppliers sell pulleys with only a pilot bore hole which will then need to be machined to the correct size. I have access to my brother's machine shop so that part is not a problem.
From what I understand, the HTD tooth profile has more backlash that other profiles like AT, ATL or GT. I want as little backlash as possible. Some manufacturers also sell pulleys with slightly undersized grooves so the belt teeth reengaged on both the leading and trailing edge.
I started having a look at moving the motors back to the outside of the frame this evening, but I'm having a hard time letting go of the belts and pulleys, I really like that setup, so will do some more research to see if I can find a local supplier with reasonable prices. I'd rather buy locally than from overseas, because international shipping is still very slow, especially with Christmas just around the corner.
I found your CNC build thread today and will read it and continue following. It seems most people want to use their machines for similar reasons, ie. woodworking and aluminium. I'm looking forward to catching up on your build thread. It's always so interesting to follow other peoples projects.Yes my ratio is 1:1 since the machine is made for milling wood and soft metal,like aluminium etc, also the gantry of the cnc is going to weigh about 45 kilos.
I know that shipping from China is a problem, same thing here.
About htd pulleys I don't have a previous experience but I have read that is not as bad as you mentioned.
On the other hand if there is backslash it will not be a problem to change them.
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