Completing the drag chain installation on the Bantam

I need some reminders how I'd intended to install the drag chain for the carriage electrical (and coolant?) connections on the Bantam.

Luckily I recall making a CAD model of the machine. This wasn't simply a vanity or boredom activity - I actually used it to design the various components used in converting it to CNC. One advantage of not having changed CAD systems for many years is that I can still access and mess with the work I did before my memory's horizon!

Here's the latest version of the complete machine:

Ooof, that's not right. I'd forgotten I'd actually continued to evolve the design so that the Z axis ballscrew and linear encoder were repositioned at the rear of the machine.

This is actually what I've got standing in the workshop right now.

And yes, the cross slide, carriage ad drag chain all articulate. Arguably I could do with finishing off the appearances (ie get the green paint brush out) but that is just superficial.

The original aim here was to find out what I had planned in terms of the drag chain. That is becoming a bit more obvious and the clouds of memory are starting to clear gradually.

I remounted this stainless steel cover plate that I seem to recall was intended to provide a mount for the travelling end of the drag chain. Sure enough, the drag chain fixings line up nicely.

With a few links fitted, it emerges at the rear of the X axis assembly.

And in the CAD assembly, it seems I had intended the fixed end to be mounted somewhere around 19mm from the end of the bed. This is with the carriage at the furthest extent from the headstock (at the home position, FWIW):

The height of the fixed end looks about right, as the separation of the top and bottom mounts measures about 85-90mm. 

That places the bottom side of the mounting bracket around 88mm from the bottom of the chip tray.

I'm measuring about 200mm from the bottom of the top bracket to the chip tray.

Looks as if the height of the fixed end is fairly clear. And the horizontal position (along the Z axis). So let's design some sort of base to locate the base on. Perhaps also forming a degree of shielding of the cable from swarf. Next time....

Got a few minutes on my hands later on and did the paint job:

Looks better.

IGUS energy chain modelling and printing

I'm planning to finalise the control cabinet for the Bantam lathe. This will involve hanging it on the tailstock end of the machine, using a couple of holes I've already tapped on the machine stand that line up with mounting holes on the cabinet.

To do this, I need to route the various control and motor cables in a vaguely professional manner. Previously I made a start on this but it was such a long time ago I've almost completely forgotten what I had in mind. What I do recall is messing about with some drag chain and at one point I even modelled it in Fusion as a live (movable) assembly. Nobody knows why I did that but perhaps I was just bored at the time.

Here's a previous post that describes that modelling work. And it seems I ordered some R48 series "energy cable" https://www.igus.co.uk/product/series-R48 For some reason I also got some smaller drag chain - what was all that about?

Here's the smaller stuff:

Looks the business - it's from IGUS (German), which is rather expensive but s "proper" industrial stuff.

On the face of it, this would be a sufficient length to accommodate the carriage movement. That's the only need for drag chain on this machine.

But there's one snag with this smaller stuff - it's open at the outside, which wouldn't be ideal when we are generating swarf and moving the drag chain back and forth endlessly.

Which explains why I (subsequently) bought the larger drag chain. This is the R48 model and the distinguishing feature of this version is that it is fully enclosed and is designed to withstand swarf - or at least allow reduced ingress. It has a removeable cap on the "outside" of the chain and the other 3 sides are closed, notwithstanding the need for articulation.

This shows how the covers are removed:

Like many industrial products these days, 3D CAD models are provided. But on closer inspection, it becomes clear that the components are not fully representative of the shipped products. Or to put it another way, if you were to print out those models, you'd have a hard time trying to remove the covers. 

I guess this is to stop (or slow down) the Chinese cloners. Why would you want to make your own parts when you already have the stuff in your hands? More on that later....

I've moved some of the furniture around so that I can get to the back of the machine - "let the dog see the rabbit" etc.

I need to remove the splash guard thing:

You can see the X axis servo motor here - the cables are just sitting in the swarf tray. The job got abandoned before it was finished.

With the rear guard removed, access is a bit more reasonable.

Here's the R48 drag chain:

This is one of the brackets that are required to secure each end of the chain:

That cover snaps on and off so that you can run the cables.

There's a shorter one that fits on the bracket itself

The 2 different versions are almost identical, apart from the curved extension which accommodates the articulation without allowing swarf ingress.

Those tabs on the bottom engage with these locking ramps on the main body.

Here's the problem - it's clear that The Stupid Fat Bloke removed ALL of the covers when we were originally messing with the drag chain. In the meantime, he obviously put them somewhere "safe". And now I have a length of drag chain without any of its covers. That is chocolate teapot territory. 

After spending the best part of an hour going through the storage in the main garage area (and finding nothing), I'm left with just this rack to save my bacon. Can it be in there please?

No chance. Another 20 minutes of my life has gone - and still no covers. So onto Plan B - 3D print some, so that the originals are then provoked into reappearing once they are complete.

So that requires me to model them up in Fusion. Luckily I have one solitary example tat The Stupid Fat Bloke overlooked. Let's get it done:

Print it out with 100% infill. Well that looks really shit:

But the fit is almost there.

It has a support raft but the issue is really that the layers show up when you have such a small angle to the table. 

The solution is fairly obvious - flip it on its end and use tree supports to avoid sagging of critical faces:

Like this:

That's better:

A couple of minor adjustments to "optimise" the fit and we have a solution. This is absolutely spot on - no slop or misalignment - clicks into place just like the genuine part:

I've ordered some black PA-CF filament (PA6 Nylon with carbon fibre) which should be here tomorrow. I may need to fiddle with the the settings, having changed from this grey (unfilled) PLA but otherwise, I should be able to print out a load of these.

Cover plate for GA500 VFD

Having mounted the keypad for the GA500 on the outside of the control cabinet for the CNC Bantam, I'm left with a hole in the cover of the main VFD. This isn't ideal, leaving the control circuitry exposed (albeit within an enclosure) and at the very least looks pretty crap.

But all is not lost. Yaskawa make the CAD models available for all their drives and related accessories, so it's a fairly simply matter of downloading the step file and printing it out:

This I did, directly from the STP file download into the Orca slicer. 

Looks nice, if you can ignore those ripples on the front face.

But there's a catch. That was the first time I've printed a part directly from a downloaded STP file. However, it turns out that it's actually an assembly of 3 components, including 2 covers - one for the USB cable and the other for the RJ45 cable (to the remote operator). 

Trying to remove the 2 covers doesn't end well. I got one off but the other is truly "as one" with the main body.

And when you look at the assembly, it's clear that they actually intersect. Or to put it another way, they are well and truly fused together. Damn. I should have imported them into Fusion to check them first. 

So, simple solution - hide the 2 covers and re-export the cover.

That worked out ok in the end. In another stroke of luck, I found a baby short ethernet cable (25cm or so) that was just perfect for the remote operator.

Final touch - I replaced the phase and ground cables from the VFD to the 16A receptable. They aren't screened but at least they won't burst into flame if subjected to the rated 15A phase current. I probably won't ever do the full 4kW but for low speed high torque conditions (eg tapping?), I may need to generate some high currents. Just visible in the last photo.