Starting to design out my build, looking for critique

[Chrono]

More progress, at least in the design department!

I did decide to design out the Z-axis a bit and plan on how to build it up, especially since one of my coworkers asked me the fateful question of: "Well it is technically possible to manufacture, but are you sure, that you can actually put it together like that, when it is in front of you?". With the earlier draft, I have no idea if that would be possible to actually assemble without a huge hassle, so I thought about it and came up with a better design, using screws and bent steel plates. The pink plate I will probably be changing out for a thicker aluminium one. Also something of note is that the bends and such are not accurate. I simply don't have enough time in Fusion's Sheet metal work-space, so I just went with the default settings for convenience's sake. After taking another look at your machine, since I was asking myself how to get more length out of the Z-Axis, I will probably also switch the rails to be on the sled and the bearing blocks to be on the gantry, like you did.



I also changed the size of the machine in my Fusion design to reflect my "updated" plans for size. This broke a couple things that I did not yet get around to fixing, like the floating plates and angles, as well as those two Z-Axis bearings floating in the middle of nowhere. The original size was guesstimated around 1m x 0.8m x 0.2m while I was still messing around with the base design. The "new" size I plan on having is: X: 2m, Y: 1m to 1.2m, Z: ~0.3m to a max of 0.5m. I am not quite sure about what a good measurement for the Z-Axis would be, so if there are any values that have generally found agreement in what not to exceed, let me hear it :D



For the linear motion setup, I am planning to use Chinese 1610 Ballscrews and HIWIN-style rails (note: not original HIWINs). The reason for that is that I started pricing out the build to where I now have a pretty "final" (well, as final as it can be at this stage) price for it, bar the uncertainty of import tax and the like. All in all this puts me at around a 3k € to maybe 3.5k € total, if taxes end up really high, and of course, planning in a cushion in case something goes wrong. The difference of the Chinese rails to the original ones is quite significant in that, however, with the bundle of ballscrews, ballnuts, BK and BF blocks, linear rails and slides, being 50% more expensive, when using original rails, with all other things being constant. But I still have to ask: Are those rails okay to get, or are there any known problems with them, accuracy-wise or otherwise?

I have also checked these lengths in the motor calc spreadsheet, and with the 2m axis, I would now be down to 5.2m/s rapids from 7.5m/s. Should I reduce this to get back up, or should I be keeping it? My reasoning for going as big as possible, is to get the "best value", so to speak. I don't want to be caught standing there with my pants down, when a project requires me to have big machine. Alternatively I could also go with 2010 ballscrews and up-size my stepper on the X? I might need to properly calculate the increase in price for that out.

Another thing that caught me off guard is just how much the motion controller, and especially that breakout board cost! 300€ for a control board and its breakout sound properly astronomical to me :D But alas, I also know not to skimp on the important bits.

With the leadshine drivers, and a spindle, that should nearly do it for electronics. Speaking of spindles, however, I was looking at this 2.2kW one. Is 2.2kW a good amount of power for my uses (wood, plastics, some aluminium, PCBs)? They also do carry a 3kW model.

Regarding Sensors, so far I have only been able to think of Endstops and homing switches. What else would I be needing? Another question that was on my mind, is why I need homing switches? Does the "home" need to be different from {0,0,0}, or am I missing something here?

You also mentioned software in your post. I know of Mach 3 and I also saw that they now make Mach 4. Are there any others out there, or are these ones the ones to get?


Now, on a completely new note: I have finally taken into account that I still need a table. I have chosen to keep this one on the back burner for a bit, until I got a preliminary pricing done for the machine itself, and I am now considering how to do this. Most machines I have seen so far, are using a steel table, that even reaches above towards the Y-Axis, where I have those big plates. Since I am using aluminium profiles already, I was thinking that I could just buy some more and make the table out of that. This would also allow me to slightly redesign my machine and allow for a similar design like yours, for example, with the raised sides. I am guessing that would be a huge plus in terms of rigidity, compared to my steel plates approach? I would, of course, loose some access and some space on the sides, accounting for the width of the extrusion, but with how wide the Y-Axis sled is, that should not be a problem in terms of actual cutting width loss, if executed correctly.