Jump to content
Ultimaker Community of 3D Printing Experts
Sign in to follow this  
smorgana

Crazy Stuck!

Recommended Posts

I've used another 3d printer that had a heated glass bed and had no problems with adhesion, and model removal.

Basically -- a bit of glue stick on the glass took care of adhesion, and then allowing the bed to cool to room temp after building, I'd hear a little "ping!" and the parts then just came off.

With the Ultimaker I'm having problems with adhesion -- not complaining because I know it's normal and know what to do about it..

But I'm also having a big problem with model removal.... I've tried cooling in the refrigerator to 40F, but no luck. This is happening with both PLA and ABS -- and the thermal expansion rate of those vs glass should be different enough to cause the parts to pop free.

I'm sure eventually I'll get the model off. (I've done it before), but this significantly adds to the build time/down time. I'm considering purchasing some plate glass cut to size so I can remove the whole shebang and start a new model while working to get the previous model off the plate.

I broke one model that took 6 hours to build because I made a wrong move trying to free it. oh well...

Edit:

Ok so its in the freezer now...

Here's the question... What approaches should I take to remove a crazy stuck part?

 

Share this post


Link to post
Share on other sites

I don't use Glue for PLA now, I started using it because instructions told me to.. but after a few times I tried it without and it works amazingly well at 60 degrees and you get a glassy smooth bottom.

If it's really stuck I usually try tapping it near the top of the print with something softish. (like the rubberized handle of a screwdriver) sometimes that pops it off.

If it's really stuck I use a pallete knife and poke at the corners which usually lift a tiny bit and it pops right off.

 

Share this post


Link to post
Share on other sites

 

ah... I hesitate to use a metal tool, but I'm at that point now... Freezing did not help.. Yes it's likely that the glue is an issue here.

I froze it at 0 degrees F for about an hour... and still thermal expansion rates are not helping me... maybe the thaw cycle will break it free...

The funny thing is... I think if I wanted to glue a part with glue stick to a piece of glass, I'd have trouble having it hold...

I am definitely up for forgoing glue on PLA for some test runs... but i'm kind of blocked here, having only one plate to work with.

 

Share this post


Link to post
Share on other sites

I'm having a lot of issue with that myself.

I use to spend half an hour every print with a little razor blade. I would slide it on all of the corner and then hit it with another object until i got under enough and it would pop off, but it is really hard.

Recently I tried the freezer thing, silly tho, it works about 50% of the time.

After an 1 in the freezer 50% of the time I can just pop it of by barely touching it, other time, I still have to fwist it a bit with my hands and it pop off nicely.

Other time i got to spend 30 min with that razor blade again, it is actually really hard to remove.

Some people say it always come up super easy, I don't know what they are doing!

 

Share this post


Link to post
Share on other sites

 

I'm wondering if the reason for some find it easy some find it hard can be found in platform height.

If the platform is too low from the nozzel -- I know for a fact that the first layer doesn't adhere well or at all... Wondering if too close a platform causes the first layer to adhere too well??

I did move the platform extra close for the print before this one....

 

 

Share this post


Link to post
Share on other sites

I never had much luck with the glue... I spray a little hairspray puddle on to a paper towel and spread it over the glass where the print is going to be. Every brand of hairspray works different I find. I'm using the $2 purple can now(Aqua Net) from the dollar store. I really like it becasue it actually dissolves previous prints hairspray, so it's always a new thin coat on the glass. Other brands had a build up affect. It also works just right, I can print with no brim, and a razor blade to get under one corner pops it free. I've tried several brands of hairspray, several brands of glue, and several brands of blue tape, but this purple Aqua Net is bar far the best. I think it's becasue it's so cheap...it's just the glue, and propellant...no anti friz crap, no perfumes...just glue.

My models often stick to blue tape so bad that I have to take an orbital sander to the parts to remove the blue tape. There is one brand of blue tape I have that I do not have that problem with, but I forget which one it is becasue I never labeled it and I have a stack of ten rolls of various brands :p

I've had a couple of really stuck prints along the way... I put a razor blade under one corner about 5 to 10 mm deep, then I bend the blade up and slide a spackle knife between the glass and the blade, and slide it under the part. Worked every time.

 

Share this post


Link to post
Share on other sites

Try cleaning the glass really well with alcohol and then don't use any glue or anything for PLA. It sticks perfect for me pretty much every time and when cool it pops off with a little bit of force. If your bed is too low though, it won't stick well.

I suggest a paint knife rather than other metal tools because it has rounded corners and is rather flexible so it wont damage your glass. Plus it's pretty thin. Best tool ever!

 

Share this post


Link to post
Share on other sites

I have no issues with using a metal tool; it isn't like I'm intending to stab it into the glass! (which in any case I assume is toughened).

My favorite implement is a 40mm wood chisel, very sharp. Rap it against the print bevel side up, and the print pings off. You want something sharp enough to get in under the print. I think a more blunt tool could damage the print.

 

Share this post


Link to post
Share on other sites

If you are struggling with glue (which I have never used so cannot comment) and do try hairspray on glass, it really is effective and once the glass has cooled to 40-50c it just pops off. I was advised to buy extra strength hairspray and that is what I use. I apply a light covering over the bed and wait 20-30 secs and apply a second light covering. No idea what impact it has if any but I do wait for the bed to warm up before applying the hairspray.

Sometimes I just do the centre of the bed if I have nothing large scheduled. I will normally go a week minimum before applying more spray. And I will often but not always clean the glass under running warm water before applying another coat

 

Share this post


Link to post
Share on other sites

 

Sadly, the model is still stuck and careful prying with a sharp knife is not helping... I don't like razor blades, or x-acto knives -- have scars to show for that...

Part of the problem is I'm trying not to break the model... I'll give up on that.

Other than that.. once it's off I'll experiment with nothing at all for PLA, and with hair spray.

Thanks for all the advice.

 

Share this post


Link to post
Share on other sites

Dude (or Dudette)...one word...RAZOR BLADE ... or is that two? Hold on let me google it... yeah two words unless you're talking about the song from Blue October, then it's one word :p

A plane-Jane, single edge razor blade, holding the model with one hand and prying the blade with the other, working towards you from the back side, pulling up on the model as you try to get it under a corner will do the trick 99% of the time (unless you're on blue tape, then that's a different story).

No scars no proof

 

Share this post


Link to post
Share on other sites

ah.. ok ok! Wouldnt it be funny if it only takes a minute with a razor blade? Instead I might sit here and design a wrench that exactly fits the contours of the model so I can pull it off the plate. I'd have to print the wrench though ;)

Ok.. getting over fears of sharp instruments and going in!

 

Share this post


Link to post
Share on other sites

 

niet, ne, lo, nein,nahi, nei, -- Google is fun!

I worked the full width of a single edge razor blade under each corner of the model, pried the blade up and down, and pulled on the model... Probably won't be able to play piano for a few hours...

the model has a large flat base -- approximately 2.5 inches by about 4 inches. thats a bunch of square inches of solid contact.

My wife worked it during the day with a knife... during the day it has developed a few streaks of non-contact area.

Now there are 4 non-contact ares in the corners... but it's not budging... back into the freezer!

 

Share this post


Link to post
Share on other sites

 

Now I have an answer...

Use a razor blade to get some non-contact, then use running water while prying up and down...

It finally popped off!

If the build plate was not removable... that part'd still be in there...

 

Share this post


Link to post
Share on other sites

MAN! That bad boy was STUCK! I have an awesome fool-proof idea for the next time this happens...

Here it is

Warm oven to 220 C. Place build plate in oven. Kiss project goodbye. Works like a charm... at least in theory. Not crazy enough to actually TRY it.

 

Share this post


Link to post
Share on other sites

Try the wood chisel, nothing beats it. A razor blade is a terrible idea, you don't want something that bends - and if it breaks you'll very much regret it.

Believe me, the perfect tool is a robust hand tool purposely designed to cut or separate things under a bit of pressure while keeping you safe, and includes a convenient handle to grip with. That describes a wood chisel, not a razor blade. Yes, you do need to get off your lazy ass, get down to the hardware store and buy one, but it's worth it.

It has to be a broad chisel to distribute the force, otherwise you could mark the part. I find 40-50mm just about perfect.

Don't use a kitchen knife either. You want a narrower cutting edge that you push away from yourself like a snow shovel.

 

Share this post


Link to post
Share on other sites

I never use anything on the heated glas, no glue, spray... nothing, print only PLA and XT.

Key is to keep the glas clean. I wash every so many weeks with some hand soap under warm running water.

In 99% of the time my prints pop of after the bed is cooled, but you need to wait a little longer after the printer tells you its ok to remove your stuff!! for XT sometimes even till cooled to 20 celcius.

I use this thing for removing the small line printed at the beginning of a print, key is not to touch the glas with your hands ... almost never happens that I have to use it to remove a part.

glasKnive

For very small parts the adhesion can be a problem, in this case I use a brim.

 

Share this post


Link to post
Share on other sites

Try the wood chisel, nothing beats it. A razor blade is a terrible idea, you don't want something that bends - and if it breaks you'll very much regret it.

Believe me, the perfect tool is a robust hand tool purposely designed to cut or separate things under a bit of pressure while keeping you safe, and includes a convenient handle to grip with. That describes a wood chisel, not a razor blade. Yes, you do need to get off your lazy ass, get down to the hardware store and buy one, but it's worth it.

It has to be a broad chisel to distribute the force, otherwise you could mark the part. I find 40-50mm just about perfect.

Don't use a kitchen knife either. You want a narrower cutting edge that you push away from yourself like a snow shovel.

 

Funny, cuz I think a wood chisel ( or any chisel in that size range) is a terrible idea. The pitch of the edge is too steep. It is too durable, meaning it will not give, so either the part has to give or the glass has to give, and if the glass gives, it breaks. Also, due to its edge, you are more likely to scratch the glass. Sure, it will probably work, but it's like using a sledge hammer to drive a finishing nail. You want to finesse the part off the glass, not take large hard steel tools to the glass.

Razor blades can break, yes. I don't know about you, but I want the razor blade to be the weakest link in the process. If I do something wrong, and the razor blade breaks, that's fine. How many times do you think you'll EVER break a chisel trying to get a part off? None. That's becasue it loads all of the energy to the glass and the part.

If you are breaking razor blades, you are using them wrong. They are not meant to pry up on the part, they are a very thin tool used to slide in between to the part and the glass, and at near parallel angles to the glass. If the razor blade feels like it's stuck, don't pull up on it, grab another razor blade and distribute the force around the part. I'll take a razor blade over a chisel any day.

 

Share this post


Link to post
Share on other sites

Have you actually tried a wood chisel, or is all this coming from your gut?

I tried a variety of thinner blades before arriving on the chisel idea, and the chisel works the best. A 25-30 degree bevel is perfect for cutting while maintaining the edge, which is why chisels are given that bevel to begin with. There is absolutely no danger of damaging or scratching toughened glass with a carbon steel tool unless you deliberately stab it into the glass, which I have no immediate plans to do.

If you use a razor then it is not "the weakest link in the process"... that description better applies to your hand - an uncovered razor blade is about the most unsafe option I can think of. It's all very well to offer advice on things not to do with a razor blade, IMHO the best advice is not to use one at all, as it's totally unnecessary.

 

Share this post


Link to post
Share on other sites

Hey, to each his own. If a wood chisel works, and you're comfortable using, go for it. I'm just saying that a razor blade is not a terrible idea. I've actually never cut myself with a razor blade removing parts, and I don't expect I ever will. Sounds like you've just had some bad experiences with razor blades :)

 

Share this post


Link to post
Share on other sites

I used to want the parts to pop off when cooled. Now I don't. I want just a tad more adhesion to the glass, and that usually means popping it off manually. There may come a time when you have too many failed prints becasue the part broke free from the bed during print, and you find yourself feeling the same way.

To be honest, if you're having to use a wood chisel or razor blade with much force to remove a piece then you can probably back down on the adhesion value.

I'm about 30 prints into this can of Aqua Net hairspray (the purple, General Dollar Sore brand) , and like many others before me have stated, it's awesome. The part may not just pop off when done, but you certainly wont have to use freezer tricks. As a matter of fact, I've spent the past 2 days going through some production prints I do and removing custom brim for PLA prints to speed up post process time. It works so well, that I no longer need the brim, yet not so strong that I can't pop the pieces off with my hands or a razor blade (or chisel :p)

I guess it all comes down to what you're using your printer for and what you're printing.

 

Share this post


Link to post
Share on other sites

I found that if the part was short with a lot of contact with the glass then it often didn't need glue. However if the part is quite tall, with relatively small contact area with the bed then you want to use every trick in the book: include PVA glue and "enable brim". Think of it as a torque problem: the torque applied by the print head is minimal, but if you have a very tall part and minimal contact with the glass...

The choice of filament also matters. Unlike UM PLA, I've found that ColorFabb doesn't adhere to a glass bed as well as it adheres to itself, and really needs glue for all prints. Otherwise you just end up with the filament being peeled off the bed and dragged around by the nozzle.

 

Share this post


Link to post
Share on other sites

I like the putty knives, they come in different sizes, and you can sharpen them even more, like a razor blade, but then you have a nice handle to hold. Try to get it just under a corner and tilt the blade upwards. Most of the time the object pops off.

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!