No luck with CPE

[friedl_basson 6]

Hi - 

 

First let me stipulate I am relatively new to 3D printing.  I have done my fair share of printing larger and mechanical parts (as R&D is what we do) but I want to apologise in advance if my question is a trivial one and I am simply overlooking something obvious.

 

I have modelled a part in PLA and it is time for printing the prototypes that will be used for field testings.  These parts have large flat surfaces, so initially I though bed adhesion should not be a problem, even though I am aware larger flat surfaces can come with their own set of challenges.

 

I started with the smallest of the parts, ±22mm x ±100mm x 70mm footprint, a simple bucket shaped object.  I always start with with the default Cura profiles, MAYBE altering wall, bottom and top thickness, but that is it.  The rest I leave as it is.  The first print started fine, but about 1 hour into the print, the far right corner lifted from the build plate.  From there things just got worse.  My Settings:

 

• Profile: CURA CPE default profile (also reduced speed and fans by 25% on a second run)
• Filament: Ultimaker CPE
• Printer: Ultimaker 2+
• Bed Adhesion: Tried both Brim and Skirt
• Bed Adhesion assistance: Magigoo
• Bed Temp: 70C
• Nozzle Temp: 250C
• Flow: 100%

 

After tge first failed print, I cleaned the bed with water, wiped clean again with Isopropyl and then added fresh coat of Magigoo.  Results was even worse.  Could not get the brim to stick even.  Levelled the bed again (even closer to the nozzle).  Again Brim would not stick.

 

Wiped the Bed again with water, added another fresh coat of Magigoo.  Changed brim to skirt.  At least this way the print starts, but as with the first attempt, the far right corner warped and lifted from the bed after about an hour.  I then enclosed the front, reorientated the print by turning it 90deg and cleaned the nozzle (atomic method).  Same result unfortunately. 

 

Just to make sure the bed was level, I switched to PLA again... printed perfectly.  Attached is an image of the very simple part I am trying to print.

 

Would really appreciate some help. At wits end here... 

 

Regards, Friedl.

 

Edited February 22, 2021 by friedl_basson

[geert_2 558]

Did you switch off the cooling fan? Or set that at a very low speed?

 

For PET, which I think is very similar to CPE, I always print without fan if the model allows it, thus if it has no overhangs and no bridges. Otherwise I use the absolute minimum amount of fan.

 

I usually print PET on bare glass. (Although some say this is not recommended, as it might cause a too good bonding, and might chip the glass.)

 

[friedl_basson 6]

1 hour ago, geert_2 said:

Did you switch off the cooling fan? Or set that at a very low speed?

 

For PET, which I think is very similar to CPE, I always print without fan if the model allows it, thus if it has no overhangs and no bridges. Otherwise I use the absolute minimum amount of fan.

 

I usually print PET on bare glass. (Although some say this is not recommended, as it might cause a too good bonding, and might chip the glass.)

 

 

Hi @geert_2 - 

 

I will try disabling the fan completely.  I have reduced the fan speed by 35% (off the already reduced speed in the Cura default profile), but have not reduced it to zero.  My guess would be around 50% of normal fan speed.  On this particular piece it should be a problem as there is no overhang.  Ons the other two parts, there are 'roof structures' but I use normal supports for that.  Should I still disable the fan?

 

I know I can obviously test these, but those are about 8 hours into the print and with the cost of CPE here locally, so would preferably try to avoid any misprints if possible 🙂

 

Kind Regards,

Friedl.

Edited February 22, 2021 by friedl_basson
additional info

[geert_2 558]

Without knowing your model, your printer and your particular CPE, I can only guess...

 

The best thing you could do, is cut out the most critical and most representative parts of your model, such as overhangs or bridges. And combine these into a new *small* test model which takes only maybe 30 minutes to complete and doesn't use much filament. Test and optimise on this until you get it good. Overdo in one direction, then overdo in the other, and gradually find the optimal center. This is going to cost time, but you learn quickly. Of course there can still be scaling problems later on, such as bonding that might reduce with time. But then at least you get the overhangs and bridges good.

 

[friedl_basson 6]

@geert_2 - 

 

My apologies, I thought the printer info included in the original post would help, I have a lot to learn 🙂 

 

• Profile: CURA CPE default profile (also reduced speed and fans by 25% on a second run)
• Filament: Ultimaker CPE
• Printer: Ultimaker 2+
• Bed Adhesion: Tried both Brim and Skirt
• Bed Adhesion assistance: Magigoo
• Bed Temp: 70C
• Nozzle Temp: 250C
• Flow: 100%

 

With regards to smaller model, I have printed these successfully.  It seems the detachment from the build plate happens 1hour+  into the print.

 

I will follow you advice, reduce fan speeds and increase bed temp to 80C then.  I will print the part sent previously first as it is the simplest one and was the one giving problems.  If successful, I will attempt the more complex models.  Thank you for your advice, I will post my results 😉

 

I have attached screen grabs of the the two main pieces and the assembled unit.

 

Regards, Friedl.

 

 

[geert_2 558]

My bad, I had missed that printer-info.

 

Yes, trying a higher bed temp might also be a good idea: mine is around 80-90°C for PET (I don't know by head, but I definitely increased it from the original 70°C). The bed temp has te be close to the glass transition temperature, where the material starts to become soft. If lower, bonding reduces. If higher, the part may become too soft and sag, warp or peel off.

 

What you could also try if you suspect time reduces bonding: *immediately* after a small test print completes, manually heat the bed to the same temperature as during the print, e.g. 80°C. And then let it sit for the night at that temp. In the morning, see if corners have lifted, and try pulling it off. But of course without brute force, always gently. If you print a tiny cube of 10mm, if the bonding is good, you can't pull it off. If the bonding goes bad, you can. But again, always be gentle.

 

Forgot to mention: also consider using a brim: maybe in Cura, or as a custom designed brim (=designed in CAD, as part of the model). This also helps reduce corner-lift.

 

I guess you are going to print the pale lid on its back, thus with the huge tabs facing the glass? In that case, consider free hanging supports for the tiny overhangs for the screws. But again: first test this concept on a small test model.

 

 

Custom brim around the left model (the right one is post-processed and polished):

 

Custom brims designed in CAD around the pink and orange supports, and around the cube:

 

Free hanging supports:

 

Other view of the free hanging supports: they are kept in place by the strings from the material, and are thus very easy to remove:

 

Cross section. The ribs on top of the supports are 0.5mm x 0.5mm. The inverted staircase at the bottom of the supports is 1mm x 1mm. The gaps and little "connection tabs" are designed and tested for this particular model, you may need to change dimensions for yours. Hence the need for a tiny test model, containing only this concept.

 

 

 

[friedl_basson 6]

Hi @geert_2 - 

 

Wow thank you for the comprehensive response.

 

With regards to the brim, I tried printing with one even though I initially thought (due to the large flat surfaces) it wont be needed.  The brim produced even worse results.  It would not even finish the 8mm brim before it starts curling upwards and lifts off the bed completely 🤯

 

The concept of free hanging supports are amazing!!  Thank you for the tip.  

 

You are correct, the bigger parts are printed with the flat surfaces on the bed, this way minimising supports needed.  I have been printing the supports for the 'screw flanges' with break away supports, using PLA they came away easy as well.  Have not gotten this far with CPE as I first need to get all corners of the part to stick and not curl up.

 

The strange part is that is was the very same corner that warped and pulled away from the build plate, regardless of the orientation or placement of the part.  I might al rig a small probe to test the actual bed temp and look for any inconstancies.  For now I just need to get one prototype out, preferably not with PLA  😄

 

 Kind Regards, 

Friedl.

[geert_2 558]

Yes, irregular temperature could be a factor: I once measured it, and at the edges it could be quite a bit lower. Maybe due to the rising hot air pulling cold air in from below. Also, under the nozzle-fans the bed can be much cooler, especially on small objects where that fan is continuously blowing on a small spot.

 

Also check the bottom surface of your prints: is it squeezed equally flat in all areas? Maybe if one corner is too far off, the filament is not squeezed well, and that could cause it to bond less. See the pic how my prints typically look.

 

Grease or oil also comes to mind, but if you already cleaned that area multiple times, it shouldn't be...

 

Photo of typical bottoms of my prints (this is PET):

 

 

[friedl_basson 6]

Hi @geert_2 - 

 

Looking at your photo, I could probably raise the bed (or lower the nozzle) a little bit.  Having said that, I am using the Ultimaker calibration card that came with the set of Nozzles and there is quite a bit of friction already when pulling the card from under the nozzle.

 

Do you have auto bed-levelling??  I would probably spend my last savings to upgrade even it was only for that purpose 😄  Well, that and Dual Extruders, hehe.  The UM2+ was a good way to get started with 3D printing, but for the type of models I print, I can most certainly see the need for the second extruder, whether it being a different colour or dissolvable support.

 

At the moment the only way for me to achieve dual colours, is to emboss on the one part and then phically print out the same as a new part.  Then try to insert into the embossed area.  As you can see in the image, this does not always go according to plan, even with 0.25mm nozzle 🙈

 

 

Thanks again for all the effort.  I have done a couple of PLA models of our enclosure again to make sure everything is the way it should be.  Will probably attempt a CPE print then tomorrow as they are quite lengthy prints (8 hours top and bottom each). 

 

Regards, Friedl.

[geert_2 558]

I have manual leveling on my UM2 printers. I did that according to the official procedure in the beginning. Since then I only adjust it occasionally on the fly. I start a print with a thick skirt (5 lines or so), or when printing the brim if I use brim (rarely), and then I watch closely how the first layer is, and adjust on the fly by moving the screw a 1/8 of a turn, and then watch again, etc. I think it is a little bit closer now than originally, indeed. But I only adjust that maybe once a year... My bottom layer is 0.2mm thick: I found that 0.1mm is too thin and a bit uneven, and 0.3 is too thick and gives lesser bonding than 0.2, especially for objects with very small holes like in my photo above. Everyone has his own taste: I like the simplicity of manual leveling, like manual shifting in a car, and a manual handbrake. :-)

 

[friedl_basson 6]

@geert_2 - 

 

haha, I get it... I used to drive a manual car, but since moving to Cape Town (hectic dead-lock traffic) I switched to Automatic 🙂

 

Thanks for all the tips, I will adjust my first layer to 0.2mm and see.  Might be my saving grace.

 

EDIT: Never mind, I suppose it is printing that sections as support, not infill 🙈

 

Off topic, hope you don't mind; My Cura started behaving suspicious, for some reason, the infill pattern (and density) does not change no matter how I change the settings.  See below.  I have selected triangles and as you can clearly see... the infill is not Triangles.  No matter what Is et it to, or even to 100% infill, this is the result??

 

Any idea what causes this?

 

 

Edited February 24, 2021 by friedl_basson

[Torgeir 280]

This might be support..

 

Thanks

Torgeir

[friedl_basson 6]

Hi - 

 

Ok, I managed to "solve" CPE warping off the bed by reducing the model size... kind of besides the point but at least it is a start. I also use Magigoo Flex as apposed to the standard one.

 

This now presented a new problem.  Even though the print seems acceptable, it is about as watertight a your average garden sprinkler 🙈  My first guess would be that the layers aren't fusing properly.  I am using the standard Cura settings at this stage.  The bed as level as you can get it, the same print with PLA hold water perfectly, even under some pressure.

 

I will try increasing print temp and reducing fan speed to see whether this help.  REALLY not enjoying CPE a whole lot at this stage 😢 

 

Regards, Friedl.

Edited July 8, 2021 by friedl_basson

[friedl_basson 6]

Hi - 

 

Just thought I'd give an update as I have some moderate success printing with CPE 🙂 

 

I changed the settings as follow:

• Bed Temp: 75C
• Print Temp: 260C
• Speed: 45mm/s
• Fan Speed: First 5 layers @ 35% and then 65% thereafter
• Enclosure: Close front
• Printer: UM2+
• Bed Adhesion: Skirt with Magigoo FLEX

I am not sure whether it was the change to Magigoo FLEX or the combination of a  slight Temp bump and reduced fan speed or maybe even all three.

 

It was quite a large part, about 12 hours print. I have to say, the part did not look as great as I have heard people claim CPE can deliver, but at least it stuck to the bed.  So there is that... 😄 

 

Regards,

Friedl

 

 

[Smithy 1,146]

Thanks for the feedback!

Have you also changed the combing setting? If you haven't turned it off completely, you can try to set max comb distance to 8mm, this should help with the massive strings in the print.

[Torgeir 280]

Hi @friedl_basson,

 

I could use this settings.

 

Thanks

Torgeir

[friedl_basson 6]

Hi @Smithy & @Torgeir - 

 

I have tried all three combing settings, turning it drastically increased the print time of this particular part from 5.5hours to almost 8 hours.  I am printing again today, will let you know how it goes.  Thank you @Smithy really appreciate the help!

 

@Torgeir  It is a pleasure, I really hope they work for you too.  I am hoping to get cleaner prints today, I really cannot see how people classify this as engineering filament if these are the results.  I am getting much more accurate prints from PLA at this stage 😄  I do need something stronger though, so not ready to give up yet.  All else fails, I will probably look at ASA as an alternative.

 

I am also baking my filament now before I print again, hopefully this helps with cleaner prints.

 

Best of luck and thanks again!!

Friedl

[Smithy 1,146]

Personally I don't like CPE or even more worse I hate it 🙂 

But luckily I don't have really the need to use it, I print in PLA for every day models, I print with ToughPLA for technical parts or parts which needs to be stronger (I really like ToughPLA). If I also need more heat resistance then I print in UM ABS, which prints very good for an ABS material. If I need a part for outside, sitting in the sun, then I print with ASA.

 

I only use CPE if I need the chemical resistance, for example I printed some parts for the pool which sits all the time under water.

 

I tried several brands of PETG with different settings, but never got a good result, so I avoid it when ever it is possible and honestly I also have nearly no need for it.

[friedl_basson 6]

Hi @Smithy - 

 

I am looking at Fillamentum range as we 'speak'.  They seem to have a large range of aesthetically pleasing filaments in 2.85mm and different materials (ASA, ABS, CPE, PLA).

 

I am getting to the "I HATE CPE" point, quite quickly I might add.  If I get it the layers to stick, the details are terrible.   If I try to counter that, I get layer separation.  Tough PLA seems like a good choice and I have heard good things about it.  I do however need some sort of chemical resistance (against Sulphuric acid vapours in particular) so I just went straight for CPE.  According to Wikipedia, ASA does present some characteristics that makes it chemically resistant. 

 

Maybe upgrading form 2+ to UM3 or UM5 wont hurt either, but here they are quite expensive.

 

Regards, Friedl. 

 

[Torgeir 280]

Hi @friedl_basson,

 

This might complicate things, So I'm wonder if a "top-hat" might help you. I'm using a cheap one, easy to install and can also work as a dust protector.. 😄

 

The box I selected also stick out in the front and cover the filament roll as well.

When printing, the tube and wire loom never touch the inside of the box.

This arrangement prevent cold draft to enter the print object from above, the temperature will never go sky high as the hot air escape easily. I've also installed a fan on the top so bring those nasty stuff vented off, if needed.

I would try this approach, as it worked very well with nylon and some other experiment filament I bought.

In this case, I would cover the front as well -but leave a little leak at the bottom so you can adjust a little flow through, if needed. But with the room temp you mentioned, I'll doubt you'll really need it.

May printer is always printing in the range (22-26) deg. C., but I'll still cover up to keep stable temp inside the printer. 

 

If you like to try, you'll need 4 hangers to put on the printer to support the box that is wider than the printer.

 

Here's how this box look:

 

Here is the hangers you'll need 4 of gcode file for UM2, plus the stl file:

UM2_Plastic_Box_Holder.gcode

PlasticBox_Holder_UM2.stl

 

Anyway, if you try this good luck.

 

Torgeir

[friedl_basson 6]

HI @Torgeir - 

 

Wow thank you, I will most certainly try this.  I printed ` couple of time today with PLA and CPE but experienced more layer separation 😕 

 

I cannot believe I have not done this sooner, but eventually grabbed some components and put together a quick thermometer to measure the ambient temperature around the printer.  Outside of the printer (later in the day) I measure ±16C.  It is very possible then that the temperature was lower earlier during my prints.  I will conform this tomorrow.  If your solution works for me as well, I will probably design a cover to include temperature control and air quality, so I can try our more filaments with strong odour when printing.

 

Thank you again for the files!  Have a great weekend,

 

Regards,

Friedl

 

 

 

 

[Smithy 1,146]

4 hours ago, friedl_basson said:

I am looking at Fillamentum range as we 'speak'.  They seem to have a large range of aesthetically pleasing filaments in 2.85mm and different materials (ASA, ABS, CPE, PLA).

I printed PLA and ASA from Fillamentum and it is great. PLA has some nice colors and prints like Colorfabb filament, only much cheaper. So I can recommend it.

[friedl_basson 6]

@Smithy & @Torgeir - 

 

It does look good indeed.  I will place an order today, will probably switch the CPE for ASA then, even though the video review on their CPE was very positive.

 

With regards to my layer separation problem on both CPE and PLA the past two days... I think I might have confirmation on the problem... see image attached.  Our min temperature today was 3C and max during the day was 6C 🥶  As I need to print this weekend, I will have to enclose the printer.  Will leave the thermometer I made inside to monitor temperatures.  

 

 Regards, Friedl.

[Smithy 1,146]

Quite cold, we get here in Austria 35C in the next days.

[geert_2 558]

As long as you don't have dedicated doors and covers, you could start with a simple sheet of plastic as front door: for example the sheets used to protect A4-documents.

 

I was wondering: how comes you have such cold temperatures in *summer*, and then even in Africa? But then I realised your summers and winters are the inverse of ours.   :-)