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by muzz64 May 1, 2016
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it's so cute
i love it (♡˙︶˙♡)

Hi, I really love your RATZ :) Would you allow me to sell a few of them for a non profit organization based in Austria/Europe which rescues rats and other animals born in laboratories?
They currently need a lot of money for the castration of all the male rats. The organization is called "my second life" (https://www.facebook.com/groups/609560502415385/?fref=nf). They have an extra facebook group where things are sold to pay for everything (https://www.facebook.com/groups/625747640778532/?hc_location=group).
I would plan on printing a few of them on my Anet at high quality settings (maybe 4 oder 5, depends on the interest of people). Would be great to hear from you, thanks!

It's nice to see someone giving back for a good cause....... even if they are rats :)

Happy for you to use my designs in this way and for a worthy cause.

All the best

Totally amazing, thank you! I'll let you know how things work out :)

such a cool project! this was the first thing I 3d printed. I liked the spring bite but when i pushed the tail up towards its limit the spring immediately broke. Is there a way to prevent this? did i not do enough infill on the spring, or should the opening for the tail be reduced to limit the amount the mouth can open?

Pleased you like my Ratz... it is a fun design.

The bottom line is PLA is very brittle so easy to break in areas that are thin. Treat them with respect so don't use any excessive force and they are fine...

Having said that, using more shells and greater infill will help for sure. Many slicers apply 2 shells / 10% infill by default. Using 50% infill will greatly increase the strength. However, it won't increase the print time and filament used by a significant amount because the model is hollow.

Filament brand and condition can also make a big difference...

I hope this helps.

I love your models, but can you make a dog like this?

Thanks for your message about my Ratz. I have a couple more things like this in mind already but it's a matter of getting time to do it... designing things like that can take quite a while. I'll add it to my list...

Just in case you haven't seen them, the closest thing I have up at present is my 'Scotty Dogs'. They are small but lots of people have liked them.

...and pleased you like my work!

Thanks for the adorable model.

I've tried to print the biting rat a few times and it never works out. Everything besides the top of the jaw where the teeth are is great, but the end of the jaw piece is always a small mess.

I watched the print and it looks like what's happening is that the internal "stem" is warping and lifting up. This causes the print head to rub against it each pass once it gets to the last ~5% of that particular part. Ultimately, the teeth portion are just a small disaster because the part is higher than the layer height at that point. Luckily it can get squished down and doesn't destroy the rest of the print.

Everything else prints fine, but I'm not sure what I can do to minimize this warping. I'm printing PLA with a heated bed inside an inclosure, so it's pretty ideal conditions.


My 'Ratz' is a challenging print for some machines and slicing apps... but hopefully some of the following helps you get the result you want as it's a very cool print when they come out well.

The mouth is the hardest part the print as it protrudes out on an extreme angle with zero support.... but you can't use automated support as that would lock it up internally. This is the challenge but beating it is the fun part.

They print great on my MakerBot's and the profiles for PLA limit PLA 'without support' at 68 degrees from vertical... so 22 degrees from being back to horizontal. That's a pretty acute angle so I didn't use the limit in this but it is 60 degrees / 30 degrees off horizontal. By rights any reasonable machine / app with PLA should deal with this okay but not all do.

Anyway, here's some ideas:

Make sure you are printing it solid enough. Lot's of people print my designs with less shells and infill than I have recommended. This can make them weak post printing but also not build as well during printing as the structures are too lightweight... they end up breaking down and being a mess. A fraction more filament can help. The crazy thing is skimping on filament can end up wasting more because your prints are too weak / lightweight / not well formed so you end up printing them again with more shells and infill... so you just used much more overall when you could have got it right first time by adding that small amount more.

I appreciate the 'ideal environment' you refer to but that may in fact be working in your favour in this instance. When printing at extreme angles you want your molten filament to solidify real fast... I assume your machine has a filament fan? It's there for a reason... rapid cooling. If your environment is too warm, and the air the fan is blowing is warmish, the cooling will be reduced. If that happens the PLA being printed in this area will stay soft too long and be pushed around as the nozzle does its thing. Try printing cold (i.e. room temperature in the mid 20 degree Celsius range and on blue painters tape).

Assuming your machine has a filament fan you may see an improvement by increasing the fan settings to increase cooling. This is going to make the extruded filament solidify quicker as soon as it's been extruded.

Machine vibration can also affect this... if that's the case it's not going to be easy to resolve as it's inherent within the machine.

The slicing app could also be the culprit. If the nozzle ends up working on that area to long and with a bit too much force it will rip things apart.... the thing to try here is things like rotating the model 45 degrees or 90 degrees to change the tool path. Believe it or not this can help....

Last ditch solution, not that I've done this myself but I am aware of other people doing this to deal with extreme angles.... tip your machine up on the side of the jaw (so the teeth are higher) as this will reduce the angle the jaw is protruding at from vertical. Your machine may be having problems with an angle of 60 degrees but at 50 degrees it could be fine.. so tip your machine up 10 degrees when you run the print. The filament will be less inclined to drop down. This is a bit more extreme but has been reported to help....

Hopefully something in the above helps the Ratz population increase further!. ,


I have no problems printing them on my Prusa i3 MK2S, they turn out perfect; but using my Wanhao 3 Plus the mouth is slightly deformed and lifting the tail just pushes the tongue into the front of the mouth rather than down. Pulling the tongue manually down a bit makes it work as intended, but every time there is nothing in the mouth and I want to open it, it's the same rigmarole of having to get my fingernail in there and pull the tongue down a bit before lifting the tail.

Moral of the story, get a 3D printer that prints accurately. The Ratz rock. Prusa beats Wanhao for accuracy by miles. As the price would indicate ;)

Used it as my very first 3D print. Love it!

Welcome to our fun and exciting new world... pleased to hear you like MY RATZ... print Fish Fossilz next. They're also very cool moving things.

Now that is some 3d printing witchcraft. Very well done.


Printed well they are very cool little rodents ... they always get people's attention and they're amazed by the bite

Very cool internal spring action! What design software are you using?

I use Rhino.... it's great for 3D print designing