First Build - Yet Another Alu Profile Router - 900 x 800

[CaptainBarnacles]

Personal view - F360 is well worth struggling with, although I'm not sure where you start. It is a steep learning curve at first and, to be honest, I suspect that personal tuition from a friend who knows it is the best way to go. Once you are off the ground, then the videos start to come into play. One problem is that based on reputation the best series of tutorials available online are those from Lars Christenson but they were made a couple of years ago and the F360 user interface has changed a bit since then. Not massively - an experienced user would very quickly see and adapt to the differences - but for a beginner, things like saying "Select the Model workspace" is a bit misleading when it is now called the Design workspace. I've done a bit of tuition for local model engineering club members so I'm aware of some of the problems beginners have and I'm not sure that they are addressed very well in the online tutorials. That's all true, anyway, for the CAD and modelling side of it. CAM and gcode production is a different issue where things are a whole lot more complicated but for design work, keep bashing at F360, get a bit of help if you can from someone you can actually ask questions, and you'll get there.

You will find a few photographs of my machine in a thread here somewhere. People did laugh. Nevertheless, the machine works, and it works better than i ever expected. I'm doing a fair bit of detailed machining in steel these days, which isn't bad for a machine designed and built for working with wood. Keep at it - you' ll get there!

That's exactly why there are no detailed photographs of my machine on the forum.

Re Fusion 360: I know it's very powerful, it's free and I would benefit significantly from mastering it, but every time I try to get competent in it's use I get frustrated instead and return to my old friend CamBam.

Kit

Haven't heard of CamBam, I'll take a look. I like 'free' and open source software but I have no objection to paying for good software if it gets the job done. F360 is hugely frustrating at the moment, especially so as I normally pick up new concepts pretty quickly, but I would like to persevere and reap the rewards as I've seen just how great it can be. While I'm CNCing as a hobby (for the time being) I still value my time and if I just can't get the results I'm looking for in a timely fashion I may well look into alternatives.

[CaptainBarnacles]

I have two different Y axis arrangements which I'd be grateful for some input on please. I originally designed my machine with top mounted linear rails but then thought I would give side mounted rails a try in order to lower the gantry by about an inch. The trade-off is that my bed will have to shrink by about 80mm from side to side as I've already got the gantry profiles (I know, design first, shop later - I've now got this tattooed on my forearms!).

Any opinions about the pros and cons of either would be much appreciated.

[pippin88]

On top of the side beams is fine.

Using 2 separate extrusions for the gantry is a lot weaker than one big one. If you already have them, it is worthwhile using a plate on the back to join the two gantry extrusions.

[AndyUK]

Either of those two setups will work, but unlike pippin I'd favour the second one in which the gantry beam is bolted to the same plate as the bearing blocks. In the first you have an extra joint to complicate things.

Totally agree on the joining of the gantry beams though, they should be one solid unit, preferably in an L configuration.

[CaptainBarnacles]

Either of those two setups will work, but unlike pippin I'd favour the second one in which the gantry beam is bolted to the same plate as the bearing blocks. In the first you have an extra joint to complicate things.

Totally agree on the joining of the gantry beams though, they should be one solid unit, preferably in an L configuration.

I think that I am leaning towards the second option, it does make sense that the gantry beams and the bearing blocks being fixed to the same piece should be more rigid.

Great call on joining the gantry beams together, I hadn't considered that at all. I guess a few pieces of aluminuim plate or profile offcuts would do the job.

[CaptainBarnacles]

I've been paying some attention to my X and Z Axes design this week and I'm starting to question whether I have built my gantry too high. The fully extended Z Axis looks like it could be vulnerable to excessive deflection given the amount of extension from the gantry.




What I realised is that most of the work I'll be doing will be on relatively thin material (12-40mm) so the router will be operating at full extension most of the time. I also realised that this must be a problem for a lot of machines; do most people raise the bed in order to minimise the deflection of the cutter? I would like to work material up to 100mm thick and I currently have about 120mm clear travel on my Z axis.

Rather than compromise my design to accomodate thick material do you think I would be better to design a machine to work thin material well and accept that I just won't be able to work thicker material. Being able to work thicker material was a bonus rather than a necessity.

[JAZZCNC]

Well, first I think you need to rethink your Z-axis design because that cannot possibly work how you have it shown now.?

Regards the Gantry height then it depends on what your cutting. All the machines I build have at least 100mm of Z travel and most have 150mm and will happily cut aluminum at full extension with a reasonable finish quality and accuracy using correct feeds n speeds. If you require a higher finish quality or deeper cuts or higher feeds then yes it's better, even necessary to have a lower machine or if not then a machine that is built much much stronger than your typical router needs.

To be honest I'm not a fan of the open gantry design you are using with the profiles orientated in the vertical position which is there weakest orientation. Those same two profiles could make a much stronger gantry if you made it an L-shape and put the screw at the rear.

[CaptainBarnacles]

Well, first I think you need to rethink your Z-axis design because that cannot possibly work how you have it shown now.?

Regards the Gantry height then it depends on what your cutting. All the machines I build have at least 100mm of Z travel and most have 150mm and will happily cut aluminum at full extension with a reasonable finish quality and accuracy using correct feeds n speeds. If you require a higher finish quality or deeper cuts or higher feeds then yes it's better, even necessary to have a lower machine or if not then a machine that is built much much stronger than your typical router needs.

To be honest I'm not a fan of the open gantry design you are using with the profiles orientated in the vertical position which is there weakest orientation. Those same two profiles could make a much stronger gantry if you made it an L-shape and put the screw at the rear.

OK, I've gone back to the drawing board with my Z Axis and had another stab at it.





With regards to the gantry, the profiles that I have are 80x80 heavy which I intend to brace across the back with perhaps 3mm aluminium sheet or some flat bar. I had thought that would be sufficiently strong for my needs (I'm cutting wood, MDF, ply, plastics and possibly the odd bit of aluminium), do I need to beef it up further?

Is it the case that you tune the machine's feed rates to the strength and stiffness of the machine?

I intend to use timing belts to drive 2010 ballscrews on my X and Y axes. Is it worth having two sets of pulleys and belts to gear it down for cutting harder materials?

[AndyUK]

I had assumed that your previous drawings with the spindle back-plate were making it shorter so we could see past it, but your latest drawings seem to continue the theme. Are you genuinely planning to have the top of the linear rails for the Z axis hanging in mid air like that? Seems like quite a flimsy design decision for the minimal cost of some extra aluminium plate.

I'd also doubt that the ballscrew needs to be that long - but I gather you've already purchased it?

[CaptainBarnacles]

I had assumed that your previous drawings with the spindle back-plate were making it shorter so we could see past it, but your latest drawings seem to continue the theme. Are you genuinely planning to have the top of the linear rails for the Z axis hanging in mid air like that? Seems like quite a flimsy design decision for the minimal cost of some extra aluminium plate.

I'd also doubt that the ballscrew needs to be that long - but I gather you've already purchased it?

Yeah, I see what you mean about those rails being unsupported when the Z is lowered and yes, I have already got the ballscrew.

Three options then:

- Add more plate to lengthen the router mount plate.
- Consider shortening the whole linear travel by cutting the rails and ballscrew.
- Buy another ballscrew. (perhaps a 1605 would be sufficient?) Looks like I can get one for about £33 with the supports, nut bracket and coupler so that won't break the bank.

I had previously wondered about shortening the ballscrew using my ML7. I'm not a very accomplished machinist and my biggest concerns (apart from completely stuffing the job up!) were about the hardness of the ballscrew and whether the action of cutting into the thread might make the cut wander.