Raft is perfect then its a nightmare

Hy, i have a HICTOP Prusa i3 with ABS, and when i try to print someting i usually add a raft to it just to stick better, and my problem is that the raft layer is 99% perfect, but when it prints my actual object in some parts its skips a bit and the extruder goes to the next line and my print is horrible.

Attachment 8300

Attachment 8301

After the raft my first layer is not that bad but it has some problems, then the problems are building up on each other and its a mess.
I'm printing with cura, the settings are: 0.3mm layer height, 0.8mm shell thickness, 0.8mm bot/top thickness, 15% infill, 45mm/s print speed, 240 extruder, 98 bed temp, 0.4 nozzle, 1.75mm filament. I had some good results with PLA but with ABS its a mess. My bed is good, because my raft is almost perfect.
Any tips?

What brand is the filament?

It is from here http://www.3dplastx.com/main/abs-filament-spools.html

It appears that you're under extruding with too high of a print temp. The bottom layer looks fine because the layer is compressed against the bed.

The bulging/textureing in the second picture is indicative of printing temperatures that are too high. The gaps between the filament are indicative of insufficient extrusion.

I would recommend a printing temperature of 225-230C with an increased flow rate. You can increase flow rate from your LCD with a manual adjustment (for testing at least), you can increase the nozzle size in Cura settings to trick more flow, or you can decrease the filament diameter in Cura settings to trick more flow.

Keep in mind that with the increased flow, your" bed-nozzle at Z0 gap" will need to be slightly increased a bit too to compensate since your first layers are coming out acceptable.

Okay.

The first picture is not the bottom layer, its the top layer of the RAFT. If that doesnt change anything you suggested then i will try them.

I understand.

I encourage the use of the Raft setting for the following scenarios:

1. The object has a very small footprint and needs a very strong adherence to the bed. Print with 100% filled raft.
2. The object has a very big footprint and needs to have less adherence to the bed. Print with 25% filled raft.

If your print doesn't require either of those I would highly consider not using a raft. However, the raft layer will behave identical to a non rafted first layer. Also, since you are trying to achieve better adhesion, I would highly recommend Elmers purple glue stick (applied cold) or...spend the money and get some BuildTak.

I've tried a zillion different bed adhesion products for ABS and relative to ease of use...Elmers Purple Glue stick or BuildTak. One is cheap and works okay, the other is a little pricey but works almost too well. PEI was a nightmare to remove and worked the same as Purple glue stick.

i'm using thermal material with little holes, so the first layer stucks, but sometimes it's not working and one corner comes up. This is why i use raft, atleast that was my thought that if i use it it wont come up that easy, but thats not working as it seems.

Attachment 8308

This is the thing i'm using, hope you can see it clear.

I will try your suggestions and thanks for your help :)

The adherence issues you are experiencing are typical for ABS. Lifting corners and edges are notorious for ABS. "Lifting" as it's known can be improved with higher heated bed temperatures, higher first layer print temperatures, the use of an aluminum build plate, and by reducing your Z0 gap height. Other solutions also include Elmers and BuildTak which I've already discussed.

If you have an aluminum build plate under that perforated thermal material I would absolutely pull the perforated sheet off and switch to Elmers Gluestick applied cold directly to the aluminum.

Your last picture looks okay, but it's still printing too hot.

Printing with ABS is very simple. Keep your chamber completely enclosed and preheat it before starting your print. Do this and you warping issues are a thing of the past.

I have printed ABS parts that cover almost the entire bed without any warping whatsoever. And I have all benefits of ABS to enjoy.

To the OP:

Have you calibrated your extruder?

What do you mean? I didn't do anything special, just the usual thing, like filament type, nozzle 0.4mm.

And to be honest i don't have a case for my printer, i'm about to build one as my heated bed cant go over 100 celsius.

Hi Whaitey, I think that while the advice of Lucky is good, you need to be a bit more systematic about all this.

I would suggest you to :
- first set precisely your Z0 gap, because otherwise any test you do on the flow rate will be biased by this. Do you have calibrated shims ?
- then set your flow rate right : there are tutorials for that.
- additionnaly, I would recommend checking your filament diameter, to be sure.

have a nice day

Quote:

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Originally Posted by Whaitey

What do you mean? I didn't do anything special, just the usual thing, like filament type, nozzle 0.4mm.

And to be honest i don't have a case for my printer, i'm about to build one as my heated bed cant go over 100 celsius.

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Sounds like you haven't calibrated it. Go to the flashforge forum and look fir the stickied Sailfish manual thread. In the first post is a link to the manual. It will be very helpful, even if you aren't running Sailfish. Especially chapter 5!

or you could simply go back to printing with pla :-)

Why struggle unnecessarily with abs when pla just works ?

yes, but i got 4 abs packs and my pla is gone, so i have to print with abs, and to be honest, i want to try every single filament i can. i will try that manual, thanks for the info

Calibration should be done regardless of the filament you use. And should be done for each material change as different materials have different values.

Okay, i removed that thermal thing so there is only plastic, i applied hairspray, heated bed to 100, nozzle to 240, levelled my bed, tried to print, then i saw that the filament is just making a huge blub on the nozzle, so i decraised the distance, it didnt work, i then raised the distance, same again, didnt work, so now i'm at the point where the printer cant even print the first layer, because its always making a blub on my nozzle. My personal opinion is that my extruder fan is working at 100% and its making the filament dry so fast. i put my hand under the fan and i can feel the wind the fan makes, and if i extrude some material i can clearly see that the fan can blow my material a bit. Any tips?

For ABS you need to turn the fan off (0 %) during the whole print. The fan is only usefull for PLA as it needs one. ABS definitely not as it has a very high glass point around 105 C (this is where it becomes rubbery) and the fan will cool it to below this way too fast.

As to the levelling, are you using a piece of paper to gauge the distance?

i actually have a feeler gauge, so i'm using that 0.1mm to level. My 12V fan is mad, if you are saying that i need to unplug that then ok.

Quote:

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Originally Posted by Whaitey

i actually have a feeler gauge, so i'm using that 0.1mm to level. My 12V fan is mad, if you are saying that i need to unplug that then ok.

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With ABS it's a safe bet to just unplug your fan. However, you can easily disable cooling in Slic3r which accomplishes the same thing.

It might just be me, but I've had much better results with my cooling fan with ABS. I've been able to get much better finishes from my FFCP.

Okay, a bit of update.
Attachment 8329

This is what i always get at the start of my print. I set up everything, i level everything when hot, i even stop the print at the start, and level the bed again just to be sure that its good, but still the same result. Any tips?

Another update:

It seemed like my bed was not levelled. I was trying as hard as i could but nothing happened. Yesterday i wanted to do some more levelling but i realized that my Z-axis switch just broke (i didnt do anything with that, simply bad quality) and i didnt get any spare ones, so i'm going to buy a proximity sensor.

The question is: what sensor should i buy? The company where i bought the printer sells this "upgrade" for 50$. What the hell? SN04-N NO , this is the sensor they are selling. Do you recommend this or another one?

EDIT: I have some expensive sensors (OMRON E2S, BES00KJ from Balluff). Where do i place them? What is the best place?

I would steer clear of the inductive sensors (the "upgrade") until you really get your printer under control.

Here is what 99% of the world uses as Endstops:

http://www.ultibots.com/endstop-microswitch/

They are great, simple, accurate switches. No reason to get all fancy with something that makes it more complicated for 2% more accuracy.