El Beast - Initial design phase, comments and critique welcomed!

[Zeeflyboy]

Couple of jobs done today, nothing overly exciting sadly!

I made my drill jigs after a few changes to my design to allow me to use it in multiple places.






Stage 1 in trying to get a nicely aligned machine, I laid it down on the ecocast bed plate and re-assembled with that as my flat reference.




Flipped and inserted spring T-nuts for retaining the bed. I also plan to drill through into the long extrusions once the machine is assembled for some alignment pins that will allow the bed to be removed and replaced without losing alignment.




With the machine now right side up, I had a first go at my method for aligning the rails to the bed reference and thus hopefully each other. I used a 1mm piece of shim brass and using a clamp I moved along the rail tightening as I went. I'm wondering if it is worth making a DRO setup to read divergence from the bed in Z to verify.




I've been thinking about the easiest way to verify that the rails are equidistant along the whole travel to a suitable level of accuracy. I'm thinking that one the motors and rail mounts are hooked up I could make a piece that spans the gap between the two side mount plates that can float in X. Fit a DRO to that and take measurements at each of the cross support points, shim if necessary. Thoughts?

[1Jumper10]

I'd forgo the DRO and just surface the bed when you have it all together. It would then be as perpendicular to the Z axis as possible. I think your brass shim method will get you very close to perfect.

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[Zeeflyboy]

Oh there will be a milled tool plate, but that method doesn't work here.

Imagine that one end of a rail is lower while the other rail is totally level. If you machine the bed flat then you'll have a nice level reading from a dro in the spindle making you think you have a flat bed. In reality it would be twisted towards the rail that is lower at one end.

That was the importance of using this eco-cast bed as a flat reference, since its basically the flattest thing that I could find readily available at reasonable cost. To do things properly and get the best end result, it needs to be as closely aligned to the ecocast plate as possible before moving on to milling a separate took plate once the machine is assembled.

It's one of the challenges of mounting these rails on the side. If they were flat on the plate then it would be a non issue.

[1Jumper10]

I understand what you're saying but the rails don't have to be co-planar when you mount them on the sides. They just have to be parallel. The manufacturer's method of mounting two rails is set one where you want it, then use it as a guide to set the other. So in this case, you'd set your first rail then use your gantry connection to the other side to guide the second rail into position. Either way, you've got a fantastic machine going and I'm sure you will get it mounted to your liking. Enjoying watching it come together.

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[Desertboy]

Looking very good there, I considered a tooling plate bed for my machine but the cost is over £500 + the VAT lol so decided that 25mm sheet of mdf would be ok for now after all.

I love how tidy she looks I can't think of 1 CNC machne you can buy I've seen that looks even close to how tidy and professional yours looks.

[Ger21]

I understand what you're saying but the rails don't have to be co-planar when you mount them on the sides. They just have to be parallel.

In this case, it's the same thing. If they are parallel, then they are coplaner.

[Zeeflyboy]

Another day, another part.

Today I bashed out the side mounting plates. I'll need to make some more shoulder screws as I have used a similar alignment strategy to the gantry slider plate to ensure alignment.






I also had my first whoopsy moment on this project - the lead out from the contour of the first part went crashing into the second part and I missed it on the simulation. Oh well, the small gouge will be a reminder that I'm a moron.




Good indication as to how much chunkier the new machine is - even the mounting plates make the X6's arms look skinny:

[RobC]

Every day I come by and check your post to see what you have done. Super job!

[Wolverine4u1]

Wow! Zeeflyboy...

What a assume and inspiring post you have .. That is one excellent machine you are building. I have a million questions as I want to build something like yours with my students but I will read more before I ask to many repeated questions. Ones that you already have commented on in your post. Do you have a set of drawings that I could look through?
OH sorry ... my rude .. My name is Dale and nice to meet you...
Thanks for a excellent read.. Dale
Thanks

[Zeeflyboy]

Cheers, though its a toy compared to some of the beasts on here (looking at you chaz!). Don't have any drawings, what are you after specifically?

Rob - ta!

I noticed today that I've had a bit of a design snafu. My motor mount model was mislabelled - the model is a mb10-c and what I have are mb12-c.

Thankfully I caught it before I made the x or z parts, but it means my ball screws are 3mm too low at the motor end as the mb12-c is a little taller.

So options are:

- Buy 2x MB10-C (bad... about £60 each and it isn't great for consistency)

- Re-machine a new front face plate with the ball screw bearings moved down by 3mm (I'll have to order more aluminium... not great but cheaper than two new motor mounts). Will also require a small design tweak to the ballnut mounts.

- skim the motor mount plates down by 3mm. Downside is they were only 10mm to start with so would be getting a bit skinny.

I'm leaning towards option 2. Really annoying - good lesson to verify all models are correctly labelled before using them! Could be worse, at least I caught it before it caused problems on all the axis.