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

[CaptainBarnacles]

Yes, that's exactly what I mean. Makes things a lot easier regards setting up and ball-screw alignment.
Getting the ball-screws aligned correctly makes a massive difference to performance and the life of the screws. Just a little off and you'll get binding which robs power and causes excess wear on the ball-nut.

Cheers for that Jazz

It's stuff like this where years of experience really show. It all looked good (to me) on my plan but the practicalities such as being able to access screws or adjust alignment etc just don't become apparent (again, to me) on a model. I would have been stuck into the build before having one of those "d'oh!" moments.

[AndyUK]

Cheers for that Jazz

It's stuff like this where years of experience really show. It all looked good (to me) on my plan but the practicalities such as being able to access screws or adjust alignment etc just don't become apparent (again, to me) on a model. I would have been stuck into the build before having one of those "d'oh!" moments.

One trick I used was once I had the design all sorted, I put it to one side and started the assembly from scratch, bringing in each component at a time and working out how to attach it, and zooming out to see what access I'd have at each stage.

Still doesn't totally work - but it helps a lot. There are still two bolts that I have no idea how to access under the gantry!

I wouldn't wait too long before adding bolts into your model - the heads can be large enough to change things, and then you might want to think about countersinking them. This ties in with the adjustment Jazz is referring to; there might be places like the Y axis ballnut connection where you want a bit more adjustment room. For example, here I used slots so I didn't have to be spot on on the height of the screw vs the rails. How would you adjust each connection in all three axis? How will you tighten the motor belts? etc.

It was all very overwhelming at the start, but now I'm looking back I regret not going that extra mile with the CAD and thinking of ingenious limit switch placements to hide them away from everything. Its a little irritating trying to retrofit them now. Obviously that's not a concern for right now, but I'd at least consider it before starting the build. The same goes for covering the screws and rails somehow - I'd prefer my build if they were protected from chips, and lubrication pipes to make everything easy to lube when its in place.

[JAZZCNC]

Cheers for that Jazz

It's stuff like this where years of experience really show. It all looked good (to me) on my plan but the practicalities such as being able to access screws or adjust alignment etc just don't become apparent (again, to me) on a model. I would have been stuck into the build before having one of those "d'oh!" moments.

It's common for the little details to get overlooked and it's the little details that can make a big difference to how the machine performs and ease of maintenance etc.

I model all the major mechanical components individually in CAD right down to the exact mm and with every hole for bolts etc in their correct locations. Then I build sub-assemblies with the components ie: Z-axis, Gantry, Ballscrews with end bearings and ball-nut mount, this lets me check for clashes with bolts, etc.
Then finally I build a full working assembly with the sub-assemblies all mated together accurately. This way I can check every detail and catch if any interference or if access is restricted etc. You'll be surprised just how easy it is to miss quite obvious details that would be major problem after parts are made.

My personal opinion is that making mock-up parts from MDF etc is a waste of time and provided you are accurate with the cad models then it's not required and defeats the purpose of CAD. Every machine I build is done solely in CAD with each part machined straight from the model and they fit together perfectly every time. (Unless I screw up the machining which never happens.!. .Honest.!!)

However for those who don't have good CAD skills or use lower-level packages that don't allow mating and assemblies etc then I agree it's a good and safe way to work.

The best advice I can give is to build in as much adjustment as possible and pay close attention to bolt hole locations/access to prevent clashes. Think about the little details right at the start like Limit switch locations, Energy chain mounting and paths, Cable routing and access to grease nipples, etc.

Break the machine down into segments and think about how each segment interacts with the next. ie: Z-axis and how it mounts to moving axis on the gantry and how the Energy chain runs along gantry and mounts to moving access does it clash with ball-screws or motors or limit SW etc when moving.?
These little details can be a right ball-ache if left until the machine is built only to find out there is no way to avoid clashing. Often the difference between something fitting or not is only mm's and can completely screw the job up or cause major part remake or big compromises on design.

The extra time in CAD is well worth the time and frustration it can save, not to mention expense if screw up big.!

[Kitwn]

However for those who don't have good CAD skills or use lower-level packages that don't allow mating and assemblies etc then I agree it's a good and safe way to work.

This probably applies to most of your readers.

MDF can be the old man's CAD. Perhaps we need a new acronym? MAD..... Model Aided Design

Either method will help you avoid creating a TURD... Totally Unbuildable Router Design