A few years ago I posted in a DIY forum how embedded printing works.
Wasn’t really a big hit back than but picked up quite a bit since.
I used to for electronics and magnets that had to be inside a print.
But of course hitting pause, adding a pre-printed cover for larger voids and such is now all obsolete and one can find a ton of videos about it.
Since no one ever gives credits I thought I might just provide some more hacks that especially those new to printing might like.
-
“Direct” printing…
I came up with the idea after I realised that some filaments ruin your build plate if you mess things up - they get permanently stuck.
So why not make this an advantage ?
For example, I needed a small honing disk for my sharpening projects - a spinning one.
The real deal costs a fortune but quality sandpaper in 2000 or higher grit is quite cheap…
I printed a simple mount for the motor part right onto the glass…
Had to wait for it to warm up on the bed but that’s about it.
Sometimes I even do repairs this way LOL
Like a plastic housing with impact damage…
If it is a flat side and can be placed with the flat part up it is printable…
The bed levelling for such projects in Bambu is a total pain though, means I use a different machine for this…
I even use plastic primer on tiles and then print directly onto them. -
Skeletons…
Sometime you just need a great support for something, like a little board you want to raise up for additional storage.
Some people then create nice looking Eiffel Tower like structures or include fancy holes…
I just print something like a flat support wall (to be slotted in later) with an extra wide infill but NO top or bottom layers…
Much faster and with the many patterns available usually also good looking. -
Windows…
Several years ago a friend of mine approached me and asked if I could print him some buildings for his model train set that occupied a 4 car garage…
Not the Merklin Mini club scale…
He was nice enough to provide me with the 3D models he created, well, SVG ones actually I had to turn 3D but easy enough.
There was just one tiny problem…
Making it fit together with fingers like for laser cut parts was easy - he wanted actual windows …
Sadly he meant PRINTED windows…
The reason for this was that he wanted a slightly frosted ‘glass’ and that in several colour tones, like white, yellow and light orange - to make it look more real he said…
So how do you print thin windows into thick plastic walls ?
YOU DON’T !
I just used the embedded printing approach.
But I pre- printed a few beds worth of two-layered sheets in (more or less) matching filament colours.
Cut to size and dropped in like for other embedded projects - with a drop of glue for Justin… -
Screw-less…
Let’s face it: For some things we need multiple parts and only too often screws or bolts to fix them together.
And some people design models this way just to avoid having to use glue.
I try to use screws only if I know the parts have to come apart later.
Like when making a scraper with blades to replace…
But if you just need to get two split parts together because you printing them this way to avoid a massive amount of supports…
I like to use PUSH-IN-PINS.
They work like a screw, just without the thread and the resulting tension.
In the most basic form I have the hole diameter just big enough to force the pin inside - basically making it permanent.
But there is also the option for larger pins to make them slotted and a bit conical on the INSIDE hole.
A 2mm hole is a great fit for a piece of filament - to be abused as a spreader to lock the pin in place.
If it ever has to come out again I drill the filament out and can still use the pin again a few times.
The spring spin is great for snap fits.
Like the above the pin is slotted, I only do two halves…
But the bottom halves are like a barb hose fitting - one barb…
The slot matches what the barb adds plus a tiny bit more to make getting it easier.
The hole has a matching lip or just a larger diameter at the bottom for the barb.
Push it in and once past the lip the barb pops open again and the pin is fixed in place. -
PLA water forming…
Ever wanted a really smooth but CURVED wall on a print ?
Or had a little accident and wanted a properly matching splint for your finger or entire hand/wrist ?
Whenever we want something like this we face the problem of how to design such a part followed by the nightmare of printing it.
So why bother if we can cheat ?
PLA is not just very forgiving, it also goes quite soft already at moderate temperatures.
If you print just a few layers of PLA in solid you get a sheet.
Print it on a smooth plate and it is a shiny sheet…
Put some water in your frying pan and the sheet inside.
Once the water starts to steam a bit the PLA is already soft as…
So no need to hurt yourself by boiling it
If you design a simple mesh or just use the honeycomb infill without top and bottom layers you get a very formable sheet…
Perfect to adjust to very organic shapes, like your hand… -
Fake vase mode models…
Vase mode is just great when it comes to getting a really nice surface and not using much filament at all.
But what about strength ?
I mean: Wouldn’t it be great to being able to print a shelf or such in vase WITHOUT it being too flimsy to sustain any loads?
Or to print a stackable container that does not require any infill while still being strong and having a double wall ?
In vase mode we only have a single wall, so how can we make that two ???
Start your design journey with just a small, square box.
If you ever checked vector files for laser cut boxes you already get an idea where we are going here…
A gap/slot of just 0.185mm (more or less - try with your machine and filament) makes the slice just accept it as being no mistake or error in the model.
Means, rather than ignoring it and going over it in a straight line, the slicer follows the path of the slot.
If you then also LEAVE about 0.185mm to the other wall your printed model will have the walls of the slots and the end of the slots fused together.
Works really nice if you create them in a grid pattern that is angled.
Of course you need to get creative with the top of the model…
Perfectly flat means the vase mode leaves it open…
And angled top of 40 to 60 degrees seems to work great to fool the slicer and to close the top.
Means a lot of design work if you are not familiar with it but saves a ton of filament of suitable models… -
The tumbler…
Getting a great surface for later painting or such can be a true pain in the behind…
With a bit of DIY though you can make your own little (or big) rock tumbler…
Quite handy if you print figurines or such quite often…
There is a ton of tutorials, videos and such online showing you how to build all kinds of rock tumblers, in all sizes you can imagine…
What they won’t tell you though is how use with plastic parts…
Rock, metal parts and such are HEAVY, our prints rather light by comparison.
Means the grinding/polishing media has to fit this problem…
Imagine something like a printed castle in a big, rotating bucket filled with sand…
Yes, good luck getting it out in one piece…
Same story for a rather delicate figurine with lots of thin and flimsy parts - you would risk breaking them or grinding the away.
So we would only use a tumbler if we have enough parts, SUITABLE parts…
Like rounded objects that won’t have too many thin parts sticking out…
A neat way to do this with far more printed models is to ‘thin down’ and replace the sand with some finer grid.
A few and cheap bags of grinding / polishing powder made from aluminium oxide or silicon carbide will last a very long time and can be washed and re-used many times.
The key is to use a mix of very fine grit and a bit of course grit, like 80% 800 grit and a mix of 200 and 400 for the remaining 20%.
This is than thinned down with light stuff, dry saw dust, baking soda or plastic powder you got from putting some leftovers and failed prints in the tumbler…
Do not overfill the tumbler with parts or mix and use a rather low speed.
If you print a lot that will be painted later on this might be worth to think about one day… -
Flame treatment and baking powder…
Not just for printed plastic…
It is great to have all in one glue and some dedicated glue for our more complicated printed models.
PETG or Nylon can be a pain to glue…
If you a flame on the to be glued joints you can overcome a lot of the impossible problems…
Give the mating areas a fine sanding, then go over it with a soft flame until the surface changes appearance.
In most cases the dull sanded areas will get a slight shine…
Glue that works on normal plastics will then also glue these special plastics, even PETG and Nylon.
Superglue is cheap, quite strong and easy to use - if you are careful with your fingers and run offs…
With the above treatment it will work on those plastics without the need for expensive activator pens that dry out so quickly…
Keep in mind though it still only cures in the ABSENCE or air…
Means for those often too large gaps we can cheat with baking powder - cures the glue instantly and goes rock hard.
MEK or PVC pipe primer can also be used to prepare many plastics for a much stronger bond.
You even use PVC glue…
BUT: The stuff is rather harmful to your health and contact and breathing in should be avoided.
If you have kids, pets, plants or such around the flame treatment is preferred, same if you still value your health.
If you must use it then please do so outside and with the wind coming from the back… -
Getting a really special surface…
Printing in different colours is as great as painting a model to get the best possible result depending on the needs…
Did you ever abuse the paint approach though ?
Apply a thin layer of acrylic clear paint and apply some pigment, sand, glitter or corn starch…
Blow off the excess, repeat if must or missed some spots and give it another clear coat - or leave it as is to better fake a rock or such things.
You can even do this to apply some fabric onto a print while leaving the surface free of the paint or contact glue.
Quite a few colours can be found as pigments for concrete or resin casting, often surprisingly cheap.
Aluminium powder, despite the hazards, can provide a really shiny and actually metallic finish with a few layers and good polishing, but I prefer the dull look…
Hydro dipping is another great way to treat a special model… -
Tapping threads rather than using nut inserts…
It is a lame and obvious one I know but many people won’t tap a thread because they think it is too hard to get right…
Sometimes it can be hard to accommodate a nut insert in a model.
Adding just a deep enough hole and tapping it is often far easier.
The only ‘complicated’ part is to select a good diameter for the hole and to have enough walls for large diameters.
Ideally you print the hole in a diameter that allows you to start tapping right away and without drilling the hole out first.
Plastic is SOFT and these tools bite quickly…
Using a bit of silicone spray provide good lubrication and prevents things from sticking.
Use other oils if you plan on painting the model as the silicone will make this next to impossible.
The key is to turn back often and the free the tool from the leftovers if need be.
And well, unlike a nut insert, your thread will only be as strong as the print - keep that in mind please.