[Furious stamping]
First up a quick announcement, a short while ago I made a website so that I can more easily
make information and downloads associated with videos like this available. If you click
the link below you can go directly to the page associated with this video where you
can get hold of the files used in this video as well as my TPU profile for prusaslicer.
I'll be gradually uploading more profiles as time goes on so look out for that too.
There's a separate video to announce some other stuff too so look out for that.
Last time I tried to make stamps was my first ever video, and it wasn't that successful.
Although I managed to achieve some results, I wasn't happy with them, imprints were fairly
poor and unclear and the stamps weren't transferring enough ink to be that usable.
Given the overwhelming popularity of that video and a number of people asking
me to try again (zero) I decided that I'd give it another go and try to work out what
went wrong and whether I can improve on it. Obviously I can as you've already seen in
the intro so let's get on with it.
I broke out the original stamps from last time so I could look closer at why they don't
work that well.
If we look at a professional stamp, or I guess you could call it a commercial stamp as it
came from poundland here in the UK so professional is probably a stretch, but you can see that
the construction is nothing spectacular, but the rubber is capable of giving smooth prints
and really detailed outlines, it's out performing our last attempts quite a lot. I think we
need to keep our expectations lower than this, after all we're not using the ideal material
- apparently - but this is an example of peak stamp, it's a good base for comparison.
As you can see here on ours, the edges are okay on this stamp, but the texture of the
print is very visible and it has lots of missing areas. The edges of the stamp also touch the
ink and leave marks on the paper. This was the least worst stamp, if we look at others
we can see that none of them are great.
It seems like one of the main issues is that the stamp isn't making constant contact with
either the ink or the paper, or the material isn't good enough to hold the ink - which
would be pretty hard to fix but not impossible.
So the first thing I wanted to do this time around was to design a system to hold the
stamps so you could have multiple stamps and one handle and switch between, then print
a decent heavy high infill handle, so I did this in fusion 360. It's actually surprisingly
hard to get the right clearance because you're mixing TPU and PLA but I got there in the
end.
I thought about a number of potential experiments to run, and thankfully I didn't have to go
through all of them because the list was very exhaustive as you can see on screen now. The
main improvements that I wanted to explore was the design of the stamp imprint itself,
smoothing the print either with printing techniques or post processing, flexibility of the stamp
itself, orientation, texture, and support materials. This in itself was quite a list
which is why it took longer than usual to create this video.
Take one wasn't terribly successful. I tried simplifying the logo and printed in PLA, this
honestly wasn't a massively serious attempt as I knew that TPU was probably the better
material, but I didn't want to keep having to change filaments so I decided to start
with PLA while doing the handle, then I could get both the sizing and tolerances sorted
at the same time as ruling out PLA as a stamp material. Which I think I pretty much did
- PLA is pretty poor at this. I assume it's just due to a lack of flexibility. Let's take
a moment to consider that anyway, I think it's worth doing
If we see a crude image of a stamp being imprinted, and this is not about the ink, because the
ink pad is squishy so any surface would get a good coating of ink. I'm talking about printing
it onto a flat sheet of paper. Paper is not really squishy so any part of the stamp that
doesn't make good contact will not leave a good imprint. If you don't have any flexibility
in the stamp, nothing can move out of the way in the already squished parts to let lower
parts touch the paper.
So in theory, it makes sense to have a material that allows compression in this direction
pictured in order to get the best impression. This is of course TPU, but not just that,
the design of the stamp's base also factors, more on that in a minute.
While we're on digression, if you want to make a stamp logo I might as well tell you
how I did it. I started out in Inkscape and drew a design. What's important to remember
in inkscape is that any design work you do based on stroke thickness will not transfer
to fusion 360. Fusion 360 sees any stroke as just a line, with no depth, so don't waste
your time messing about with stroke width, colour, style, etc.
Before you save this move the whole thing up to the top left corner, because that is
what fusion sees as its zero point. It makes moving the design around a lot easier. Then
you can save as svg.
In fusion, you simply choose import svg and I recommend doing this as late as you can
in the design because either I'm being stupid or you really can't easily move or edit svg
imports after you place them. Which is annoying.
Once done, just extrude out the design forwards, and the base backwards. The reason you pull
the design down instead of up is because it will then be reversed, so you don't have to
reverse it, but if you did want to you could do that during import.
The next tests were done with TPU, and used a more outline based design with no thicker
areas, and these came out better on the whole. I would guess that when you print thin areas
of TPU then it allows a bit of flexing which means you get a good coverage. I noticed still
though that on the legs of the chip here some bits would miss out quite often presumably
because they were too low to contact well even with that flexibility. We are making
progress though, if we do a side by side comparison, this is better.
I experimented with printing at different depths of TPU and couldn't really find a sweet
spot where it allowed enough squish without the edges of the stamp touching the paper.
It was at this point that I decided to move on to the next test, which was to print the
stamps upside down. This is a massive technical challenge for some designs because not only
do you have to get all the letters and fine details to stick down to the bed without moving,
but you also have to support the base of the stamp somehow.
I will release a separate video in a couple of weeks or less on how to tune your TPU settings
to achieve this kind of output, for now there's my last TPU video which appears now that should
get you some of the way.
On the second point, to support the base, it's not that hard actually. Because TPU is
flexible and soft enough to cut easily with clippers I opted to put some circles in the
design, extrude them down with the stamp, then clip them off after printing. This works
really well, I recommend keeping them fairly small because bigger ones are harder to clip.
You essentially want to put them in unsupported corners and where there's large gaps, to aid
the bridging. Again having your TPU settings dialed in will help keep this neat. It's actually
quite amazing what you can achieve when everything is working right.
Once this was done, I clipped off the support posts and tried the stamp. By the way be sure
to use eye protection when clipping off supports, they might be soft but you still don't want
them in your eye.
This result is better, but something was not quite right. On looking at Prusaslicer's preview
I noticed the obvious mistake I'd made, there's a thing called elephant foot compensation
and this is to control horizontal expansion of the first layer. Without getting too technical,
it was messing up the resolution of the first layer so it needed to be turned off.
This made a massive difference and at this point I was getting really satisfying results
as you can see here. Compare this with the face up version.
Next I wanted to include text, so I did, and it soon became obvious that the stamp was
lacking the necessary detail. There's really only two ways out of this - either scale up
and make the whole stamp bigger, or try to increase detail with higher print resolution.
Since we're printing flat on the plate the only way to do the second option would be
to change to a 0.2 nozzle, and I did try a 0.2 nozzle, but I can report that this does
not work well at all. TPU and small nozzles is a nightmare. I now have a printer that
needs repairing as it's completely bunged up with TPU. The pressure against the nozzle
just causes havoc. So, the only answer is to scale up, which I did.
This time I designed the stamp with the points I'd learned up to now in mind, so that it
won't need any supports. This is a point I want to stress, which I will also sum up later
on but it's important to design a stamp with what works well right from the beginning.
If you already have a logo it might not be suitable at all for a stamp and you're going
to struggle to get good results. Bold simple lines work best, without too much detail.
This is the logo for my new channel where all my electronics stuff will go, and yes
I pretty much designed the logo for a stamp and that will be the channel logo.
Anyway same as before, I printed the handle in PLA with a decent infill for weight, then
the stamp in TPU, upside down with supports, and it worked really well. I was very pleased
with this, this turned out to be a usable stamp, you wouldn't even know it was 3d printed.
At this point I also realized that to create a circular stamp, you can save a lot of effort
by just using a circular base. I also abandoned my reusable base plan as I figured I was getting
pretty good at knowing when a stamp will work well enough to want a permanent base on any
stamp that looks good from now on. So back in fusion 360 I made a circular handle, and
went with an overall diameter of 48mm. A circular handle is easy enough, just draw the rough
shape then revolve it. I honestly don't know why I didn't do this to start with.
Once the stamp and base were completed I used standard superglue to stick them together,
you need around 3 hours for this to dry during which time it's absolutely necessary to clamp
the stamp face down onto a flat surface, if you have spring clamps like I do then this
method works really well. Be careful not to have any glue spill so you don't literally
glue the stamp down, I actually use superglue gel as it's less runny and it also seems to
last longer in the tube without going dry.
Oddly once this was glued and dry, I found that the circular stamp didn't work as well,
and it took me a while to work out why. There certainly wasn't anything to do with the stamp
handle or the adhesion.
It's actually to do with the squishiness not only of the letters, but the base behind the
stamp. As I mentioned before the whole stamp has to contact the paper to get a good impression,
and the base is kind of a mattress behind the letters. It was at this point I started
to mess about with different depths and infills and realised that the best way is to use an
infill that allows vertical displacement, this would be something like gyroid. You can't
infill the stamp detail and I don't think that's necessary, you just need enough behind
the stamp's design to allow the functional parts to push back.
If your printer is struggling to print some separate letters out as I found was the case
with a couple of the thinner letters on this stamp, like the I kept ripping off after a
couple of layers, then the answer to this is to either slow down, add more supports
in the vicinity or do what I have done here which is to add single layer supports on the
first layer, this usually does the trick. Because they're just one layer tall you can
easily clip them off, but make sure to avoid putting them on curved parts of the design
as you don't want to have to cut a curve shape off. To do this by the way you just need to
extrude to your print layer height, which is usually something like 0.2mm, that's what
I'm using.
Also when I printed circular stamps without the outer rim here, I found they peeled up
off the base mid print and detached entirely. You can solve that by a design like this with
a sort of ring around the edge connected by a few 1 layer thick joining pieces, again
easy to cut off afterwards and this solved the problem entirely.
As you can see, at this point I have basically sorted this method of making stamps. If I
weren't doing a video I would stop here and consider this a success. But there was one
more method I wanted to look at. After my previous video one of the viewers suggested
that I should sand down stamps after making them, this would apply to stamps made face
up. So I printed out the same stamp face up, and took some 320 grit sandpaper to it. TPU
doesn't appear to sand very well as you might expect, but after maybe 10 mins of just rubbing
the stamp on the paper I saw a huge improvement in the performance of the stamp. So they were
right - sanding stamps does work, and this result is almost as good as printing face
down, if you had a design that you couldn't print face down, or a textured bed that isn't
glass, then sanding is actually a good method to use.
I want to point out that I tried to create a draft behind the stamp design to make printing
easier and perhaps improve the quality but two points around this. First, I didn't find
it improved quality, it didn't make it worse either.
Second and most importantly fusion 360 just didn't want to do it. On simple shapes it
is happy to create drafts but when it comes to text especially it just gives error after
error. I'm far from an expert so I may be doing it wrong but I tried drafting after
extrusion, and using a taper while extruding, and I found that fusion was giving errors
that were inconsistent and got fed up of the whole thing, and given it wasn't really obvious
that it was going to give better results anyway - I just left it there. I did briefly consider
using another CAD but honestly, it would delay this video by probably a month while I learn
how to use it, and for what?
So anyway, The last couple of stamps I made were rectangular and were largely done as
props for this video. Making a permanent rectangular base wasn't too hard, just extrude a rectangle
then on the shorter side draw the same kind of handle shape, then revolve it and create
a compound shape - try to spread as much of the handle's load onto the base as possible
so that you don't have a weak handle but that's all there is to it.
Again I used my temporary posts method and trimmed them off after printing. I was surprised
at the level of detail I was able to print without any of it coming off, remember that
I have provided my TPU stamp profile for prusaslicer on the website, but the main thing was to
print very, very slowly with lots of retraction. Yes, retraction on TPU - the next video on
TPU is going to make some waves no doubt because I go against a lot of preconceptions on how
to print TPU, but I will let my results speak for themselves.
With this stamp I coloured different parts of the stamp with different inks for an interesting
effect.
Finally I pushed the boat out with the stamp you saw in the intro, nothing too tricky in
terms of design. I want to mention though that this stamp printed out perfectly first
try. The TPU profile works that well, that not one letter on this stamp came off, nor
did I need to bridge letters like before. That's impressive. Of course if I had needed
to bridge letters, I would have, but I guess the progressive tweaks I had made to the printing
profile over the course of making the video made this a lot more reliable, so I do definitely
recommend trying my profiles out. By the way I've never actually shared prusaslicer profiles
before so if you have any trouble importing them then it's probably my fault, let me know.
Well that brings us to the summary of the video and don't tune out at this point because
it's got some important advice at least in my opinion.
Firstly you can print TPU stamps either face up or face down, but face down requires less
post-processing, but is harder to pull off successfully.
Sanding is best done with a fine grit, just go at it for a few minutes in a circular motion.
Don't bother with any non flexible material, it doesn't work.
Use supports when printing face down, clip them off after.
Putting a rim round the edge of a stamp not only looks better, it helps the print turn
out better.
Keep designs bold and simple, it's actually important to design a stamp from the ground
up, if you try to use an existing design that has too much detail it just won't work well.
It's a hassle but it's just how it is.
One thing I haven't mentioned up to this point but I think it's worth stating, stamping with
this kind of stamp is something you have to take a bit of time over, you can't just whack
it down and get an imprint, you have to spend some time loading the ink up, then apply even
pressure to the paper.
And finally as I already mentioned, all the resources and profiles used in this video
are shared on my new website - see the link below.
Well that's it. I think I can probably put stamps to bed now, finally I have achieved
what I wanted to in the first episode. Let me know in the comments what you think, or
if you've tried yourself and whether it worked out. Remember to subscribe and like. Thanks
for watching!