From Prusa to Bambu

[Dr.Al]

If you're not at all interested in 3D printing, now might be a time to go and read a different thread. However, I thought some might be interested in how the transition between manufacturers goes for me.

As anyone who has followed any of my build write-ups will have realised, I get a lot of use out of my 3D printer (5300 hours of printing time so far according to the statistics screen). It still astonishes me how many different things become just a little bit easier because I can quickly design and 3D-print a little widget / jig / wall mount / marking gauge or whatever. I've had the 3D printer for a few years now and I've been thinking for a while about upgrading to a newer / better one. I few months ago I mentioned this to my other half and she said "well, you can certainly justify it given how much you use it". I'm not sure I can really justify it, but not wanting to argue, I nevertheless decided to buy a new one when the Black Friday sales came round.

The essential things I was looking for in a new printer were (in rough order of priority):

1. Bigger print area. I'm deliberately saying "area" rather than "volume" as I regularly hit the XY size limit of the printer (and have to print parts in multiple pieces) whereas I don't think I've ever hit the Z size limit of the printer.
2. Not too much bigger overall printer size. The printer lives in the dining room and there isn't that much room for a substantially bigger printer (in particular, the Prusa Core XL is far too deep for the space available).
3. Faster print speed. Newer generation printers seem to run a lot quicker than the older ones (according to some CAD models I tried in Prusaslicer, the Core One is about twice the speed of my Mk3s+ - I generally trust the Prusaslicer time predictions so this seems a fair comparison).
4. Automatic first layer calibration. First layer calibration isn't something that has to be done often: mainly when changing nozzles, but it's tedious and time consuming (to the point that I avoid changing nozzles unless absolutely necessary) and it would be great to never have to worry about it again. A lot of the newer printers do first layer calibration automatically, so I considered that an essential requirement.
5. An enclosure and extractor fan to make it practical to print some more exotic materials like ABS/ASA. This could be retrofitted onto any printer (including my current one), but an integrated one tends to mean a smaller overall size. The enclosure shouldn't have any negative effect on printing PETG (i.e. I still want to be able to do this with the enclosure's door shut).
6. The slicer must support STEP files (most do) as I really don't want to go back to the dark ages of STL files.

A few nice-to-haves but non-essentials I was hoping for were:

1. Automatic filament changing. This provides two main features: multi-colour printing (mainly for labels on the top of a part) and also ideally for dealing with the end of a roll of filament (i.e. just switch to the next roll of the same filament when one runs out rather than waiting for me to come and manually swap). There have been a few times when I've left a print running overnight expecting it to be finished in the morning but when I've come downstairs I've found it still had several hours to go as it had run out of filament.
2. The ability to print more easily removable supports of some sort (either PVA or some type of transition filament). I do my best to avoid supports whenever possible, but being able to use easily removable supports would offer some more design freedom.
3. Built-in network support would be nice (to save the faff involved with setting up a Raspberry Pi with Octoprint). No big deal if not though as Octopi works well.
4. Multiple extruders, especially if they can be used with different nozzles sizes (e.g. print most of the object with a 0.4 mm nozzle and then add a layer of embossed text with a 0.2 mm nozzle and a different colour filament).

After a lot of wavering back and forth between the Prusa line-up and the Bambu one, I settled on this rather expensive beast:

I definitely had a strong leaning towards Prusa as I like the fact they're made in Europe, that their support is second-to-none (even long after warranties have expired) and that they provide upgrade paths to convert an older printer into a newer one. I came very close to opting for the Prusa Core One or Core L (either which would have been a lot cheaper than the H2D!) and if the overall size of the Prusa Core XL had been just a little bit smaller overall I think it would have won the battle. However, this machine is quite a bit more capable in a lot of ways than the Core One and (with the exception of the build area) the Core XL.

An example of the benefit to me of the bigger build area is the drawer liners for my travel tool chest. This is what a print would look like sliced for the Prusa (spread over three separate prints):

Here it is on the H2D:

Of those ten criteria above, the only one it doesn't really meet is the multiple extruders one, despite having multiple extruders! It has two extruders (which will be useful for support material or mixed TPU/PETG prints), but it doesn't support having different nozzle sizes on the two extruders. Hopefully that will be resolved with a firmware update at some point in the future, but there are no guarantees.

It's early days yet, but there are a few negatives I've found so far.

The first was a disappointing set-up "experience". I carefully followed the un-boxing instructions in the booklet that came with the printer, but neither it (nor the un-boxing video on their website) mentioned one little bit of foam tucked away at the back of the printer behind the nozzles. I didn't notice it (it was only visible from some angles) and it resulted in the initial calibration failing. The error message was just a generic "calibration failed" one with a QR code that took you to a generic web page with no information about that error. I tried contacting support but got a message saying the response would take 2-3 days so I tried deciphering the QR code and doing a web search for the error code embedded in the URL (the error code disappears when you follow the link as it forwards you to another page, but you can find it with a barcode scanner). That brought up a forum where someone was having nozzle problems, so I had a look around the nozzle area and found the foam.

When I had problems with the Prusa printer, I used the live chat on their website (which is available 24/7) and got help almost immediately.

More to follow...

 

[Dr.Al]

These are the first things I printed on the H2D:

They are slightly pointless prints if I'm honest; I'd already printed one (in monochrome) on the Prusa. However, it seemed like a good test of a few different things and it was a relatively quick thing to start with.

Speed wise, it was very good. It took a long time to get started: it runs lots of "pre-flight" checks for things like bed levelling, vibration compensation and nozzle offsets. That takes nearly 10 minutes! I've done some prints in the past for which the entire print took less than 10 minutes; however, most are multiple hours and hence the 10 minute warm-up is largely irrelevant. Once it got going, the speed was excellent: the Prusa took 2 hours to print one of those pieces; the H2D took 2 hours to print both.

The reason I printed two of them was that it gave me a chance to try printing in two different orientations. One is face down (the way I printed it on the Prusa), the other is face up. The face-up one needed supports (which was partly why I did it - as a test of support printing). This is what the two of them look like in the same orientation:

The one on the left was face down and has a bit of a speckled texture from the bed; the other was face up and doesn't look great but at least is smooth.

For the supports I used some "Support for PETG/PLA" from Bambu that is used as an interface material between the support and the print. The idea is that it doesn't stick especially well to the print and you can easily pull the supports away from the print. In practice, digging the supports out was quite a chore and, as you can see from the photo above, it left the layer of support interface material on the print. That's not a problem for something like this, but it could be annoying on other parts.

I've read that PLA can be used as an interface material for PETG, so I'll try that at some point. I've also got some PVA, which can be used as a support and then removed with warm water. That's a more expensive option, but it'll be good to try.

This photo shows a comparison of the top surface of two parts printed in the same filament. The one on the left was printed on the Prusa; the one on the right on the H2D. The finish is fairly similar (any difference in the image is just lighting).

This photo shows a comparison of the bottom surface of two parts printed in the same filament. The one on the left was printed on the Prusa (using the "Satin" build plate that I always used); the one on the right on the H2D. I much, much prefer the finish from the Prusa plate.

Bambu offer two different build plates for the H2D. The other option (which I don't have) is called a "smooth PEI plate". I expect that will leave a better finish on the part, but it requires the tedious extra step of applying glue to the plate before printing PETG. That seems like a big downside to me compared to what I'm used to with the Prusa.

On a semi-positive note, it looks like there are after-market build plates with a satin finish and they look like they might be similar to the Prusa one. However, it's made and sold in America and the shipping to the UK is extortionate (especially considering there's also a note to say that import duties may be added as well). This might have to go on the wish list and I'll think about it if I ever happen to visit the USA, although I doubt that'll happen any time soon.

 

[EBME2]

Have you tried the ‘ironing’ function in the slicer? It seems to run over the top layer slowly in the opposite direction without extruding. Was on for one of my downloaded ones and was really smooth top layer. Keep forgetting to try it again for my own models.

 

[Dr.Al]

No, but I definitely will, thanks. I think I explored it with the Prusa but on the model I tried it with it added so much to the print time that I decided against bothering. I'd largely forgotten about it since then, so thanks for the reminder: it might be a good option on the faster printer.

 

[Kram]

Bambu offer two different build plates for the H2D. The other option (which I don't have) is called a "smooth PEI plate". I expect that will leave a better finish on the part, but it requires the tedious extra step of applying glue to the plate before printing PETG. That seems like a big downside to me compared to what I'm used to with the Prusa.

Smooth should work ok without glue. I've been using the patterned smooth plates, PETG and it sticks well to them. Lots to choose from on amazon, they all come from China and near enough the same - some might not have logos and need build plate detection turned off, which I couldnt really care about.

I'd be interested fo know, does the H2D default to 55 degrees bed for PLA? My brothers A1 sets to 65c. I had some issues at 55 but none above 60c.

 

[Dr.Al]

Smooth should work ok without glue. I've been using the patterned smooth plates, PETG and it sticks well to them. Lots to choose from on amazon, they all come from China and near enough the same - some might not have logos and need build plate detection turned off, which I couldnt really care about.

Thanks, that interesting. The Bambu Smooth plate specifically says to use glue with PETG - hence my comment.

I'd be interested fo know, does the H2D default to 55 degrees bed for PLA? My brothers A1 sets to 65c. I had some issues at 55 but none above 60c.

No idea at the moment; I haven't used PLA with it (I think I've only printed about 3 things ever in PLA).

 

[Dev]

but it requires the tedious extra step of applying glue to the plate before printing PETG

It might be a PEI plate so PETG and flexible filaments bond extremely well - so the glue is a barrier.

 

[Dr.Al]

It might be a PEI plate so PETG and flexible filaments bond extremely well - so the glue is a barrier.

Yes, I think it's called PEI, so that makes sense.

I miss my Satin sheet

 

[daedalusminos]

I'm in need of an upgrade too, but will hold out to see how you get on....I'm very tempted to hold out for the Bondtech INDX system for the CORE One

 

[Dr.Al]

I'm in need of an upgrade too, but will hold out to see how you get on....I'm very tempted to hold out for the Bondtech INDX system for the CORE One

That looks like a good option and you really can't go wrong with a Prusa. The Core One L was really tempting for me.

 

[Kram]

When testing the Esun "PET" I copied the Bambu PET-CF settings of 100c bed temperature, using the textured PEI, the brim was extremely well stuck and took some effort to get off - I dont use scrapers.

Yes, I think it's called PEI, so that makes sense.

I miss my Satin sheet

Do they make a build plate of similar size, this looks like it should work, perhaps with slight careful modification.

XL Satin Powder-coated Print Sheet | Original Prusa 3D printers directly from Josef Prusa

Eshop by Prusa Research a.s., company founded by Josef Prusa, one of the RepRap core developers. We're selling Original Prusa 3D printers (incl. Prusa MK4, Prusa XL), filaments (especially our in-house made Prusament), resins, and other accessories for 3D printing.

www.prusa3d.com

Note some printers use the plate for nozzle cleaning. The P2S has a seperate stainless steel area for that.

I did see a recommendation for this brand, they do a plate

Sheet for Bambu H2D

Premium quality double-sided 3D printing sheet Dimensions: 320x350 mm Amazing adhesion – no glue needed Long-lasting Flexible steel sheet Easy oil visibility. Attaches to magnetic beds If your printer does not have a magnetic bed, check out our magnetic sticker pads. Fit to: Bambu Lab H2D...

oseq.cz

 

[Dr.Al]

Oooh, that looks promising, thanks @Kram. I'll have a browse of the Oseq site later. It had occurred to me I could get a Prusa Core XL sheet and modify it, but it would be much nicer not to have to!

The H2D has a separate area for cleaning like the P2S.

 

[Dr.Al]

This was my second print and it highlights the speed benefit of the new printer quite well. This would have taken 24 hours on the Prusa (and if I wanted it with coloured text I would have had to do two manual colour changes); it took 6 hours on the H2D and all was automatic.

The third print (in a very rare example of me printing something someone else designed) was a tray to catch the filament that gets ejected out of the back of the printer. When I first saw the print head cleaning itself and drooling down into a receptacle, I assumed that there was a little tray that needed to be emptied periodically (which would have been fine with me). When I tried to find it, I realised it was just a chute so it could "poo" the filament out the back.

There's now this tray on the side to catch the rubbish (which is a bit excessive in size really; I may design a smaller one in due course). This included several parts that are way too big to have ever imagined printing them on the Prusa (although, of course, I would never have needed them with the Prusa!)

Another negative for me is the "Bambu Handy" app. Ostensibly, this is a useful tool to tell you what's going on with the printer. You can see a live video from inside the chamber (which is great) and you can see how long prints have left. That's all good. It's also supposed to pop up a notification when the print finishes, although in practice, it pops up notification at some point after the print has finished; sometimes a few minutes later, sometimes a few hours later, sometimes shortly after you've started the next print, which is a little confusing.

For the Prusa, I used to use OctoApp. As well as all the live video and (timely) notifications of success / filament run-out etc, it had a "sticky" notification that showed how long is left and (most usefully) what time it would finish. With the Bambu one, I have to open the app, see that it's got (say) 3 hours and 25 minutes left, then look at the clock and add that time to the current time. Only then will I know roughly when the print will finish.

It looks like you can enable LAN-only mode and Development mode on the H2D and then OctoApp will work with it, so I'll probably give that a try to see what it does; I doubt it'll have all the features (as some will depend on "push" notifications from the printer), but it definitely looks worth a try.

If space (and negotiations with the other half!) weren't a consideration, I'd keep the Prusa printer. That would be great as I'd probably never again be in the situation of waiting for a long print to finish before I could start something else going (as I could start the second print on the second printer). The Prusa has been brilliant and incredibly reliable (once the first layer calibration is done, it really is a fire-and-forget type of printer). Alas space is too much of a consideration (and I told my other half I'd be selling the Prusa to offset the cost a little!) so the Prusa is going up for sale.

 

[Dr.Al]

The new printer also has a couple of other tricks up its proverbial sleeves: a vinyl cutter and a laser cutter. The laser cutter is limited (as it isn't that powerful and is obviously limited to the same build area as the printer), but should be quite fun to play with and I'll report back on how that all goes. I have a few specific uses in mind, one of which you'll see the beginnings of in this post. I haven't thought of anything I'd do with the vinyl cutter.

This was one of the main things that tempted me away from Prusa. While a proper laser cutter would undoubtedly be better than something that bolts onto a 3D printer, the bolt-on option means I don't have to find space for a separate laser cutter and with the limited space I have, that's really valuable to me.

These were the first things I did with the laser cutter, partly just to have a play. The wood is basswood (which I think is the American name for lime) plywood, which came with the printer. As you can see, the results on the left-hand ones were a bit mixed, but that was down to the "Birds-Eye camera" needing calibration and once I'd sorted that out and tweaked the speed/power (which was very easy to do) the results were better.

Switching between printing and laser cutting is a very quick process: move the filament reels out the way, pop the lid off, drop the laser onto the tool head, attach the air pipe and power cable and then swap out the magnetic build plate for the laser base plate. It only takes a couple of minutes.

One of the things I'd like to do with the laser (as you might have guessed from the wooden logos above) is add my logo to things I make. I've got a "touch mark" - a brass stamp with the logo cut into it that you heat up and apply to a piece of wood in order to mark it. It works okay, but it has a couple of downsides. Firstly, it's a bit finickety: you have to get it hot enough but not too hot and you have to be careful to make sure it's aligned perpendicular to the part you're marking. Get either of those wrong and you've just messed up the project you've worked so hard on. The second problem is arguably one of economics. When you buy a touch mark, it's obviously a fixed size, so if you work on a project that's a bit smaller you either can't mark it or you have to buy a different size touch mark.

The laser will itself be limited (as the finished part must fit inside the enclosure) but it'll be a lot more flexible for smaller projects like boxes and turned bowls (where I'm more likely to need a smaller mark). For larger projects I can either use the touch mark or mark a smaller part before it's attached to the main project.

That introduced an interesting question in my mind: can I laser mark previous projects to which I've already applied an oil or wax finish? To that end, I prepared a pile of scrap bits of wood of a variety of different species. Most of these were planed with a smoothing plane but I also prepared two blanks (one Iroku and one Sweet Chestnut) on the lathe and sanded them to 240 grit. The turned ones got a sanding sealer and beeswax finish. The planed ones got a mixture: some were left unfinished, some had hard wax oil, some had Mike's Magic Mix.

With the blanks prepared, I set about attacking them with a laser. I was quite nervous about doing this and watched it like a hawk while it was running: "burning" and "oil" aren't two words you usually want to string together when you're sitting by a shiny new 3D printer in the dining room! However, in the end it was absolutely fine and produced some nice results:

The flat ones were quite straightforward. I tried a calibration pattern (which varies speed and power) on a bit of Sweet Chestnut as a starting point and that gave me a speed and power setting to default to. Most of the bits I tried worked fine with that first speed and power setting; only the Cedar of Lebanon needed a little more power to get a good mark.

The turned ones were slightly more challenging. Again, the speed and power was absolutely fine. The issue was that on the first (Iroku) sample, I just picked a point on the top for the (automatic) height measurement and then started the engraving process. It seemed to work fine but when I looked at the part the logos were all really distorted. That was because the top of the turned part wasn't perfectly flat (it bowed up in the middle slightly) and that was enough to mess up the look of the logo.

Thankfully, the printer has another trick up its sleeve: a curved surface engraving mode, where you get it to measure the height of lots of points over the area you're going to engrave and then it automatically adjusts itself to conform to the shape. This is the Iroku block after I'd done two runs. The first run had three different logo sizes and all looked distorted. There wasn't much space left for another go, so I just did the second run (in curved surface mode) over the top of the first one and (ignoring the overlaps) it looked much better.

This is the Sweet Chestnut one, which also had a slightly curved top, but for which I did it in curved mode straight-away:

The next thing to do is to try it on some actual projects (which is a bit daunting!). There's still some doubt in my mind about how it will cope with trying to engrave in the pocket on a bowl that was turned in that way, but the first try will be on one I don't like as much!

After an inevitably initial flurry of activity, I'm probably not going to do a lot with the laser over the next few months for the simple reason that it needs a ventilation pipe fed out through the window - it's a bit cold outside to have the window open so I can see the laser being something I use more in the warmer months!

 

[Dr.Al]

After chopping up a bit of plywood (with a 90 mm hole-sawed hole in it) to cover the window while letting the vent pipe out, I had a bit of session of logo-engraving on the bowls I've made.

This is a live view from the internal camera while engraving the first one:

It was absolutely fine with engraving at the bottom of the pocket (although it wouldn't have managed very much deeper):

As I plodded through the bowls, a couple of them came out with a rather distorted logo (which I sanded off before reapplying finish). I initially thought it was something going wrong with the height measurement thing but I eventually realised the problem was that the bowl was moving during engraving. The laser head moves back and forward quite violently and shakes the whole printer, so it's not that surprising that a bowl might shift.

For the later ones (and the re-runs of the ones that were distorted) I used some little magnets (that came with the printer) to hold the bowls in place:

After a couple of hours of working through the bowl collection, I'd engraved logo and date into 28 bowls (of the 29 I've made: there's another one on my desk at work). Here are a few examples:

 

[Dr.Al]

I'm really growing to dislike the textured PEI build plate that comes with the Bambu printer. PETG sticks far too hard to it so I've been having to use a (plastic) scraper to get the support bases off on any prints needing supports. The bigger prints pop off okay when I flex the sheet, but small things don't. This was never a problem with the Prusa satin plate.

 

[Beanwood]

I'm really growing to dislike the textured PEI build plate that comes with the Bambu printer. PETG sticks far too hard to it so I've been having to use a (plastic) scraper to get the support bases off on any prints needing supports. The bigger prints pop off okay when I flex the sheet, but small things don't. This was never a problem with the Prusa satin plate.

Interesting - how small/thick ? My 35mm discs regulalrly pop off quite happily after a little cooling and flexing?

 

[My Old Landy]

I run three textured plates. Once the print finishes I swap plates. Once cooled the print pops off no matter what size.

 

[Beanwood]

I run three textured plates. Once the print finishes I swap plates. Once cooled the print pops off no matter what size.

I run 2 for the same reason

 

[Dr.Al]

Some of the little support bases are about 15 mm diameter or less. Some of the bits of support base that have stayed on the plate are about 5 mm square. A build that finished this evening (and had been left for an hour to cool) had about 8 little 5 mm squares that all had to be removed manually.