A 3d printed six string....

[rwillett]

And this is what happens 10.5 hours into an 11 hour print when the print head nudges a nut and crashes the print... Oh what joy... Got up at 05:00 to start the print again <sigh>

 

This is what the inside of a large print looks like at 20% infill. That's the cross section in the middle of everything. As you increase the infill, the cross section gets denser and denser. 20% infill is 80% air which sounds quite fragile, but a 20% infill print is quite strong. I wouldn't want to make a step ladder out of it, but for most usages where there is no real stress on an item this is fine.

 

 

For more stressed parts of the guitar, such as the neck module which holds the neck on through screws, I print at 60% infill. This is very strong and hold compression quite well. All the parts of my CNC machine I made that hold the router are printed at 60%, the router pushs a router bit at circa 30K RPM through metal and wood. 60% printing was easily rigid enough for soft metals, CNCing stainless steel is a different question all together and that needs all metal structures or you take off 0.001mm a time and it takes three months to cut anything out.

 

Rob

[Richard R]

This is super impressive.

It's almost a shame that you're going to fill the seams and paint it, having all the structure and guts on show would be great.

 

[rwillett]

I'll have a look at it and make a call whether to or not. 

 

I've had to use the neck off the first version so that's surplus to requirements. Wpuld test there anyway before I touched V2

[rwillett]

Someone asked me about support and infill, so I thought I'd explain it a little better.

 

This is the neck module. It will hold a small adapter that allows different bridges to be used. The adapter will fit to the bridge using the number of M3 holes in tourquoise on each side of the module. You can see one side below.

 

The red screw holes are for the pickguard.

 

The three large holes in yellow in the middle horizontal section are for Telecaster bridges which appear to have long screws in to hold the pickup adjustment, longer than 19mm anyway. For the purpose of this we can ignore the holes.

 

 

The blue horizontal section, the middle of the 'H' shape fits between the 15mm plywood backbone and the bridge adapter. If we print the module horizontally, this section is unsupported. We can get away with unsupported sections around 4-6mm, not 100mm. Not going to work. One option might be to change the printing orientation of the bridge module, print it on the end so that it's vertical like so

 

 

There are three issues with doing this.

 

1. Any holes will come out as ellipses as gravity takes its toll. So the large three holes in the middle would need to be designed as ellipses in the vertical axis so they sagged down to a circle. Doable but a pain.

2. Any face that is printed on the print bed, comes out very smooth and very nice. The back of this module is hidden and so this nice smooth surface is wasted.

3. The strength of the module is compromised as the longest filament length is either across the back or from the sides. We want the filaments running long to provide the strength.

 

Sp to get around the problem, we design it how we want it to work, and in the slicer program, PrusaSlicer but Cura works the same, we add in a support enforcer. This manually forces the slicing program to automatically generate support wherever the support enforcer touches the main module. Thats the blue box below. Manually forcing something automatically sounds odd, it means that I tell the slicer program where to do support and it automatically generates the support just for that area. I don't want it to auto-generate support everywhere as it then does odd things in the other holes.

 

I have turned the bridge module upside down so that the top gets the nice smooth surface from the steel plate.

 

 

If I slice it now, I get

 

 

The green is the automatically generated support. I have set it to be as simple and wide a support as I can.

 

This is the honeycomb support that I will cut away and discard. All it does is hold the middle section up.

 

 

We can see in the picture above the dark red which is the infill at 20%. I have set PrusaSlicer to generate an infill at 60% for the middle section (from 15mm from the base plate to 25mm) to provide more strength

 

This is the same model, literally 0.3mm higher. You can see the infill is far more tightly packed. I could go even higher, but 60% is fine. The more infill the slower the print

 

 

On the whole we try not to do too much support as its an effort to remove and to clean. We also want the lowest percentage of infill appropriate for the job. 10% is fine for a lot of things but a guitar has stresses on it, so this is how we handle it.

 

Hope this explains things.

 

Rob

 

Edited December 8, 2023 by rwillett

[SpondonBassed]

10 hours ago, rwillett said:

when the print head nudges a nut

 

...it's time to sit a bit further back from the job.

 

Re: supports, would it be possible to print over a block of print resistant material that is the shape of the void and that can be pulled out of the print at the end?

[rwillett]

26 minutes ago, SpondonBassed said:

 

...it's time to sit a bit further back from the job.

 

Re: supports, would it be possible to print over a block of print resistant material that is the shape of the void and that can be pulled out of the print at the end?

 <Tl;Dr>No</Tl;Dr>

 

Think about the shape of the head and the movement of the head. It moves all over the bed based on the fundamental premise there is nothing higher than it and so it can move everywhere and anywhere.  A support block would immediately crash into the head. This is the reason why you print supports. 

 

The head crash I just had was due to a nut being around 0.25mm too high. 

Edited December 8, 2023 by rwillett

[SpondonBassed]

1 minute ago, rwillett said:

 <Tl;Dr>No</Tl;Dr>

 

Think about the shape of the head and the movement of the head. It moves all over the bed based on the fundamental premise there is nothing higher than it and so it can move everywhere and anywhere.  A support block would immediately crash into the head. This is the reason why you print supports. 

 

Ah.

[rwillett]

Actually my last response wasn't quite accurate about assuming the print head moving anywhere.

 

There  is a setting to allow you to print separate and multiple objects one at a time. So each one is 100% printed and then the print head moves to the next one. This means that if the print head crashes into an object, only that object is lost. Normally you print a tiny layer for each object all at once. 

 

The disadvantage of this is that you need to leave a certain distance around the object to allow the print head to move. It's quite a large space to leave so you reduce the numbera that can be printed. 

[tauzero]

On 08/12/2023 at 07:02, rwillett said:

I'm looking for a bass neck with tuners. Was hoping for a medium scale as I think neck dive will be an issue. I'll look over the weekend for any maths around centre of gravity and levers. 

 

If anybody has a bass neck they want to get rid of, let me know. 

 

 

Neck dive solved.

[rwillett]

If you wish to donate it, that’s really generous. I'll post you the body back. 

I’ll send you my address 

[itu]

On 08/12/2023 at 15:43, rwillett said:

1. Any holes will come out as ellipses as gravity takes its toll. So the large three holes in the middle would need to be designed as ellipses in the vertical axis so they sagged down to a circle. Doable but a pain.

A good point, quite often we did machining afterwards, because of this. Printing exact shapes like screw holes is a real pain, no matter with polymers, or metals.

[rwillett]

7 minutes ago, itu said:

A good point, quite often we did machining afterwards, because of this. Printing exact shapes like screw holes is a real pain, no matter with polymers, or metals.

There are so many compromises made in 3d printing. How much infill vs speed? Line width vs quality? Printer orientation vs circles or elipses. 

 

If you machine afterwards then that's extra cost and time. Another compromise.

 

It's a heavy burden but another bottle of white may help followed by the last episode of Bodies. 

[rwillett]

I know I'm going to have to shield the various cavities. I've a roll of 10m x 20mm copper tape with conducting adhesive.

 

How many payers should I lay down for it? 1, 2 or 3. I want to be sure and one is enough, great, but if I need three layers, I'll get some more copper tape.

 

Any suggestions welcomed.

 

Thanks

Rob

[MichaelDean]

One layer should be fine.

[rwillett]

@MichaelDean

 

I was advised to put three layers but that seems an awful lot.

 

Thanks

 

[MichaelDean]

But you're creating a faraday cage. That's the point of shielding. As long as it's solid all the way round, it should be fine. You wouldn't put more than one layer on the inside of a pickguard.

[MichaelDean]

I'd say start with one. You can always add more if you need to.

[itu]

You can make a Faraday cage from a net, where the eye size dictates the lower frequency limit: the smaller the eye, the higher the f.

[rwillett]

So most (but not all) of the guitar is printed.

 

 

Still need to do one pick guard but waiting to lay out the wiring loom before I print, so I can check hole for pots. Covers for the backs aere all done. neck is done but not shown. Pickups are all mounted up, wiring loom is in a package unopened. Bridge adapter done but not shown.

 

Do I need to have an electrical connection between the back of the pickguards and the copper lining the various cavaties? I've left some copper on the top of the guitar so when the pickguard, which has copper cladding on the back, is screwed down, there will be connectivity but not sure I actually need it. If I don't need it, I'll tidy the copper cladding up so it's flush, if I do need it, I'll tidy the copper cladding up so there's a consistent and tidy 1mm overlap.

 

Any advice welcomed.

 

Thanks

Rob

 

 

 

 

[SamIAm]

1 hour ago, rwillett said:

Do I need to have an electrical connection between the back of the pickguards and the copper lining the various cavaties?

Yes

S’manth x

[rwillett]

39 minutes ago, Smanth said:

Yes

S’manth x

Thanks, so I do need to have the copper tape coming over the top to provide electrical connectivity OR I solder a wire across the areas. I'll think about what the best option is.

 

Great

 

Rob

[MichaelDean]

Just having the cavity tape against the pickguard tape should be fine. Looks like there is already some tape by some of the pickguard mounting holes. I'd say leave that there and match the shielding on the pickguard. Then you know you've got continuity because the screw is holding it in place.

[rwillett]

@MichaelDean

 

Thats a good idea, I've got the multimeter out already and am checking its all correct,

Rob

[SamIAm]

When I 3D printed a new pickguard for my first proper bass, I relied on the fact that the pots were on the faceplate and wired to ground ... I had also wired ground to the backing layer of the copper tape.  I recall I spread out the wires and then stuck some more tape on top so they were sandwiched between two layers.

 

Yes, ultimeter FTW @MichaelDean!

 

S'manth x

[Stub Mandrel]

On 11/12/2023 at 15:54, rwillett said:

I know I'm going to have to shield the various cavities. I've a roll of 10m x 20mm copper tape with conducting adhesive.

 

How many payers should I lay down for it? 1, 2 or 3. I want to be sure and one is enough, great, but if I need three layers, I'll get some more copper tape.

 

Any suggestions welcomed.

 

Thanks

Rob

 

Just one.. no benefit from a thicker layer.