Multi-Color 3D Printer

[mawyatt]

We have an ongoing project that we've printed some End Cap bumper types as shown for an extruded aluminum "channel" that acts as the housing for a custom PCB. These End Caps were 3D printed with a Genius printer which has worked well and produced nice prints.

Would also like to print thin End Plates that will fit under these End Caps, and hold the Connectors, LEDs and Potentiometers. For labels the idea is to Emboss these in the End Plates with text and markings in another color from the End Plate to stand out better. We've done this before with somewhat limited success by pausing the Genius print operation, swapping and purging the filament, and continuing.

What are recommendations for a 3D Printer which handles multiple colors without swapping the filaments, and associated slicing tools to create (automatically without user input) the files to allow the color changes?

We have occasional prototype use, don't need large print capability, or high speed, and use PLA filaments.

Any guidance is greatly appreciated,

Best,

[brucehoult]

I've done this before without even pausing the print ... as soon at the embossed stuff starts to be printed I snip the filament, and feed the new one in behind it.

It looks fine (to me) if the first layer, or parts of the first layer, of the embossing is in the original colour.

Would be nice to have it automatic, for sure, and I know some machines can do that, but I don't know details.

[dferyance]

The best kind of printer for multi-color is an independent dual extrusion (IDEX). They can get pricy. Because they are 2 or more hot-ends they don't have to purge filament. It sounds like your specific case might not need frequent color changes. If the embossing is all on its own layer and at the top, that probably isn't too bad to do with an automatic color changer. But if you have color changes within the same layer, a printer without IDEX will be purging every layer. This slows things down considerably and wastes a lot of filament.

Prusa has a color change kit as does Bambu lab. They are not IDEX unless you get Prusa's XL which has a tool-change mechanism. No idea how good that is and I don't think it is very available.

My printer has no support for multiple materials. I account for this by splitting up the part into individual single-color parts and joining them together. This can be challenging at times. You have to get tolerances just right or they won't fit together. Depending on the use case a simple friction-fit might be fine. I tend to solvent weld though.

[kripton2035]

the cetus printer can do it. and is not that pricey.
https://www.cetus3d.com/

[xrunner]

We have an ongoing project that we've printed some End Cap bumper types as shown for an extruded aluminum "channel" that acts as the housing for a custom PCB. These End Caps were 3D printed with a Genius printer which has worked well and produced nice prints.

I can't help you with your question, but thanks for the idea for the bumpers for those types of cases. That's what I want to do from now on. 

[themadhippy]

bambu offer a few options
https://bambulab.com/en

[mikeselectricstuff]

Would also like to print thin End Plates that will fit under these End Caps, and hold the Connectors, LEDs and Potentiometers. For labels the idea is to Emboss these in the End Plates with text and markings in another color from the End Plate to stand out better. We've done this before with somewhat limited success by pausing the Genius print operation, swapping and purging the filament, and continuing.

I doubt this will look very good - probably better off using PCBS as ends.

[Kean]

I doubt this will look very good - probably better off using PCBS as ends.

Agreed, but maybe fine for one-off in-house test equipment.
I imagine that a 3D printed end plate would have to be a lot thicker to have the same rigidity of FR4.

[mikeselectricstuff]

I doubt this will look very good - probably better off using PCBS as ends.

Agreed, but maybe fine for one-off in-house test equipment.
I imagine that a 3D printed end plate would have to be a lot thicker to have the same rigidity of FR4.

And the text will need to be pretty big to be legible,  & still not look great

[nctnico]

I second the suggestion for using FR4. You can even order boards without copper just to have the solder mask and silk screen.

Where it comes to a 3D printer: one of my relatives has bought one of those Bambu Labs 3D printers (P1S IIRC) which supports printing with up to 4 different colors / materials and I'm pretty impressed with what it can do.

[mendip_discovery]

I have a cetus2. It's a bit of a pain as it insists on it's own slicer which is quite powerful but not very user friendly.

I have just bought some bits so it can work with with other slicers.

[Kean]

Mike (the OP) has some experience with 3D printed face plates with embossed text using large fonts.
You can see examples in some of his many posts - like the photo here https://www.eevblog.com/forum/projects/bias-network-for-lcr-meter/msg5211243/#msg5211243

To me the large fonts and colourful plastic make the devices look a bit too much like toys, but they are still a significant step up from my sticky labels on prototype PCBs or jiffy boxes.

And I guess bright coloured plastic doesn't seem to have done much damage to Asian companies like Hakko or Mechanic... or Fluke 

[mawyatt]

Thanks everyone, have a few things to consider.

This is why this site is such a great resource, and thank goodness we didn't mention a DSO/MSO

Our use isn't for production, altho the 1st few prototypes will likely be done with in-house, well, actually our garage since CEO chased our 3D printing capability out of the house, and we weren't printing with any of the smelly stuff either, just PLA 

All fun aside, we've considered using PCBs before on a number of occasions as they are a good choice, great for one-offs, but this won't be the configuration utilized in full production. The production units will utilize a bumper design similar as shown but with a much more "rubbery" material (not sure if there is anything 3D printable similar to what is used in handheld DMMs protective cases for example) and the end plates will be punched out aluminum with quality 3M covered printed full coverage label.

Now off to look into the many great suggestions!!

Best,

[mawyatt]

We have an ongoing project that we've printed some End Cap bumper types as shown for an extruded aluminum "channel" that acts as the housing for a custom PCB. These End Caps were 3D printed with a Genius printer which has worked well and produced nice prints.

I can't help you with your question, but thanks for the idea for the bumpers for those types of cases. That's what I want to do from now on. 

These aluminum extrusions are really good for prototypes, but also for high production use. They are cheap, rugged and have good repeatability but generally don't look as good as other housings. With the end bumpers they look much better and give a more professional look IMO, as well as providing protection, and yield a very rugged solution which is necessary for the intended product.

We struggled with various housings (more than we care to admit as others (client) got involved), and "borrowed" the end bumper idea from our old Tektronix 2465 scope rear mounts, which is similar to the old HP34401 and "borrowed" by many OEMs today. Kept this quiet from our client until we had the 3D print finished and fit onto the Al extrusions, when they saw the end result they were delighted!! Problem solved finally, now to finish up the electronic and PCB design and off to the PCB fab facility.

The Al extrusion we used was the same AliExpress as used on the DC Bias Adapter mentioned by Kean, and since we had another on hand this became the baseline means to this housing, altho client didn't know.

If you are using the same extrusion we can provide the 3D print file if interested.

Best,

[mawyatt]

Mike (the OP) has some experience with 3D printed face plates with embossed text using large fonts.
You can see examples in some of his many posts - like the photo here https://www.eevblog.com/forum/projects/bias-network-for-lcr-meter/msg5211243/#msg5211243

To me the large fonts and colourful plastic make the devices look a bit too much like toys, but they are still a significant step up from my sticky labels on prototype PCBs or jiffy boxes.

And I guess bright coloured plastic doesn't seem to have done much damage to Asian companies like Hakko or Mechanic... or Fluke 

The DC Bias Adapter used the Al extrusion mentioned and 3D printed end plates. The ends also had aluminum end plates for shielding and strength.

However, these were not multi-color 3D printed, we had tried with very limited success and ended up just using Acrylic Paint Pens.

Agree it does yield a somewhat "toyish" look tho, and suspect a proper 3D printed embossed multi-color won't look much better. For the full production use on mentioned project, the end plates will be punched aluminum with quality 3M full coverage labels. We've seen this before on other similar equipment and it comes out looking first class

Best,

[Kean]

Have you looked at the extruded aluminium enclosures from Hammond?  I use the Hammond boxes on a few designs.  Buying direct is a lot cheaper than through distributors, without the high shipping cost from Asia.  Hammond can also take care of panel cut outs, and they do silk screen labeling.  I haven't needed their value add services as I can do the CNC milling in-house, and I also have access to screen-printing companies in my local area - although I have been happy with just engraving text into the black end plates.

Another labeling option to consider is mylar or similar graphic decals, as are often used for membrane keypads.  While they do add cost, they can solve other problems and can give a really professional finish.  The modern manufacturing methods mean smaller runs are much more feasible.

[mikeselectricstuff]

BTW for low-volume, high quality printed panels, especially colour, UV printing can be worth a look, either direct print or on a vinyl label

[mawyatt]

@ Kean, thanks.

Yes, very familiar with Hammond, in fact the prior prototype that hosted the 8 channel version electronics was Hammond (this version is single channel). Client ended up using Takachi Japan for 8 channel version, they were/are expensive bench mount 1st class enclosures.

However, for the single channel the size is much smaller with external Power Supply, and needs to be much more rugged and cost effective. For production we will use 3M thick plastic printed labels on ends, this will have company Logo and all details printed. With previous very expensive systems, client employed these 3M labels over large areas, and they look really nice with texture, colors and such. We have already engaged with Graphics Art company to design labels for this enclosure.

Our goal and why we requested expert recommendations on the 3D printer is to be able to quickly produce prototypes that look reasonable, as this area is likely to "spin off" multiple projects. So printing maybe 10 prototypes is probably the limit of a single print job, and having multiple colors will be "icing on the cake"!!

Best,

[mawyatt]

BTW for low-volume, high quality printed panels, especially colour, UV printing can be worth a look, either direct print or on a vinyl label

Haven't looked into anything like that, other than printing labels on an Ink Jet which we haven't done (yet).

Any information is appreciated.

Best,

[mikeselectricstuff]

BTW for low-volume, high quality printed panels, especially colour, UV printing can be worth a look, either direct print or on a vinyl label

Haven't looked into anything like that, other than printing labels on an Ink Jet which we haven't done (yet).

Any information is appreciated.

Best,

UV print on a panel gives a hard-wearing finish similar to PCB soldermask/silkscreen, but better resolution & colour range. UV printed labels also have very nice print quality, and plastic ones are also quite hardwearing, limited by the substrate material

[xrunner]

If you are using the same extrusion we can provide the 3D print file if interested.

Best,

Thanks. I tinkered with making it myself today (F360). Got the basic shape made, but it's just a first pass. I just went by what I saw in your pictures. I printed it to see how it looks on a small case I'm using for a current project. The bumpers are a little too large and a few other issues to fix, but not a big deal to make those adjustments. 

[Infraviolet]

"For labels the idea is to Emboss these in the End Plates with text and markings in another color from the End Plate to stand out better."
There is always the option to put recessed text in to the printed object's shape, then brush across it with either very runny or very thick paint (which will settle in the recesses can be varied by method), so one it dries you have the printed plastic visible on most of the surface, but the recesses filled with the paint.This will only be suitable for relatively large fonts though, minimum line widths of perhaps 0.5mm IF you're lucky and your text is on a "side"* face of the printed part.

*a face which has a normal primarily pointing on the X or Y axis, the normal being parallel to the print bed, when printing. Text on faces with normals pointed along Z will be less precise still, due to the width of the printer's nozzle and its inability to extrude an infinitesimally thin line.

[mawyatt]

If you are using the same extrusion we can provide the 3D print file if interested.

Best,

Thanks. I tinkered with making it myself today (F360). Got the basic shape made, but it's just a first pass. I just went by what I saw in your pictures. I printed it to see how it looks on a small case I'm using for a current project. The bumpers are a little too large and a few other issues to fix, but not a big deal to make those adjustments. 

That looks good!! Is the extrusion painted on outside, and what size?

The one we posted is a 110mm by 50mm extrusion that is in two parts, top and bottom that slide together.

Best,

[mawyatt]

"For labels the idea is to Emboss these in the End Plates with text and markings in another color from the End Plate to stand out better."
There is always the option to put recessed text in to the printed object's shape, then brush across it with either very runny or very thick paint (which will settle in the recesses can be varied by method), so one it dries you have the printed plastic visible on most of the surface, but the recesses filled with the paint.This will only be suitable for relatively large fonts though, minimum line widths of perhaps 0.5mm IF you're lucky and your text is on a "side"* face of the printed part.

*a face which has a normal primarily pointing on the X or Y axis, the normal being parallel to the print bed, when printing. Text on faces with normals pointed along Z will be less precise still, due to the width of the printer's nozzle and its inability to extrude an infinitesimally thin line.

Thanks, that's another possibility with negative embossed text, however this would require a thicker plate.

In this thread we simply painted the embossed text with acrylic pens, somewhat tedious but came out looking OK.

https://www.eevblog.com/forum/projects/bias-network-for-lcr-meter/msg5211243/#msg5211243

Best,

[xrunner]

That looks good!! Is the extrusion painted on outside, and what size?

The one we posted is a 110mm by 50mm extrusion that is in two parts, top and bottom that slide together.

Best,

The extrusion case is a painted one-piece, 80 x 87 mm. It came from another unit like the one next to it, which is something that was used in ham radio for digital modes. But the function it served is built-into most new ham rigs, so I'm scavenging the case of one of them for another project.

After I re-sized the "bumpers" I think the looks are good. Question for you: you don't show any front or back panels attached yet. In your design, does the panel go under the screw tabs or over them? This has to do with another design idea I am thinking about.

Were you planning on using any slip-proof material on the bottom bumpers? The plastic is not a great material for feet, so I plan on using some thin adhesive rubber on the bottom of the plastic bumpers which would sit on the table. Or you could stick-on rubber feet to the case, as long as they were higher than the bumper height.

Thanks.

[Kean]

For the bumpers, you might want to try using TPU filament.  I've read up on the options, but not yet tried it myself.

With something like the designs shown, I think you may need to adjust the model to bulk up any thinner sections as it will likely be too flexible.  You could also possibly do a part part print, with the TPU being  design as an "overmold" to get the best properties of both filaments.  If going into mass production, you can then get the overmold made in silicone.

When selecting a TPU filament, you will probably want to get one with a higher hardness rating like 95A.  The softer ones are great when you want flexible parts, but are notoriously difficult to use in some 3D printers.  Printing TPU requires a direct drive extruder.  Do a bit of a search for other users experience with your specific printer and TPU.

[xrunner]

For the bumpers, you might want to try using TPU filament.  I've read up on the options, but not yet tried it myself.

Haven't tried it yet myself because I haven't had a reason to, but I need to get a roll now and experiment with it.

OK so here's my final take on the bumper design. I wanted the edges to fit more like the bumpers shown on the Rigol function generator shown.

The white panel is only for testing and doesn't have any other purpose yet. I ended up recessing the tabs that the screws go through 1.5 mm. This so the tabs won't be seen and at the same time the front panel will have a clean fit with the edge of the "bumpers". Then I added a 1.5 mm rib on each inside edge of the panel to take up the space at each edge of the case created by recessing. These parts were printed with a 0.6 mm nozzle at a layer height of 0.2 mm for a faster print, but for the final versions I'll do 0.15 mm.

I think I'll make a post in the thread below later with the Fusion 360 files if anyone is interested.

https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/

[mawyatt]

That looks good!! Is the extrusion painted on outside, and what size?

The one we posted is a 110mm by 50mm extrusion that is in two parts, top and bottom that slide together.

Best,

After I re-sized the "bumpers" I think the looks are good. Question for you: you don't show any front or back panels attached yet. In your design, does the panel go under the screw tabs or over them? This has to do with another design idea I am thinking about.

Were you planning on using any slip-proof material on the bottom bumpers? The plastic is not a great material for feet, so I plan on using some thin adhesive rubber on the bottom of the plastic bumpers which would sit on the table. Or you could stick-on rubber feet to the case, as long as they were higher than the bumper height.

Thanks.

The front panel will reside under the "bumpers" as shown, this hides the cover plate seams. The cover plate will be aluminum with a label, or screened printed aluminum, or plastic (multi-color 3D print for prototypes), or even an aluminum or FR4 PCB type, we haven't decided yet for either prototypes or production, and will hold a push button switch, a pair of pots, and some LEDs.

These 3D prints are intended for the 1st few prototypes of a production product. The production product will use a more "rubbery" and "flexible" bumper of silicone or similar material, as it will experience very rugged handling in use, not lab use!!

Edit: This "Bumper" concept may carry over to another project and having an aluminum cover that is in electrical contact with the extrusion provides a Faraday shield which is necessary for this other project. Seems like an ideal means for a simple, low cost, rugged enclosure for electronics & PCBs. 

Best,

[mawyatt]

For the bumpers, you might want to try using TPU filament.  I've read up on the options, but not yet tried it myself.

With something like the designs shown, I think you may need to adjust the model to bulk up any thinner sections as it will likely be too flexible.  You could also possibly do a part part print, with the TPU being  design as an "overmold" to get the best properties of both filaments.  If going into mass production, you can then get the overmold made in silicone.

When selecting a TPU filament, you will probably want to get one with a higher hardness rating like 95A.  The softer ones are great when you want flexible parts, but are notoriously difficult to use in some 3D printers.  Printing TPU requires a direct drive extruder.  Do a bit of a search for other users experience with your specific printer and TPU.

Thanks, will take a look at this TPU filament type.

We aren't that comfortable with 3D printing and only used PLA so far, so may take awhile as we gain more experience.

Best,

[mawyatt]

OK so here's my final take on the bumper design. I wanted the edges to fit more like the bumpers shown on the Rigol function generator shown.

Siglent like Rigol have a similar type front "bumper" design.

Best,

[mawyatt]

Pulled the trigger on the Bambu X1 per some recommendations, we'll see how this works out. We have a few things to create for an ongoing and starting project, so having a more "refined" 3D printer without a lot of additional effort was an important decision point. Also understand that having a fully enclosed printer is important, we were just using a kludge styrofoam taped together cover for our present 3D printer, so this also helped with the decision.

We'll also give the TPU filament a try later, need to order a reel.

Anyway, thanks for the help and recommendations.

Best,