Tips For Printing A Flat Smooth Surface please

Hi all, fairly new to 3D printing but loving my Taz. I have a part, its basically a flat rectangular shape 75mm wide x 50mm long, about 5mm thick. I want to print it so one of the big flat sides is smooth. Best results seem to be if I have that face down on the bed.

But lets say I have designed something that is mostly flat but has a lump on that face so I cant print that side down (hope that makes sense).

Are there any tips or tricks for being able to have the flat places nice and smooth, or am I stuck with the lines from the extruder nozzle if that makes sense.

You will always see and feel the lines of the extruder. That’s unavoidable by the way your printer is working.
You can minimize roughness by calibrating your e-steps perfectly: This is best done printing low layer heights like 0.1mm and searching for voids between lines with a strong magnifier. If there is no void, decrease esteps value by 1% until you get voids. increase esteps again by 0.5% until all voids are gone. Now you are dead on!

Printing slow helps with surface quality. 20-30mm/s will give a very good result, but takes a lot of time.

Thanks so much for the the tips!!!

So this is a photo of what iI am trying to print. Its only the 4 corner “flat” areas I am concerned about. Can I get a better surface finish than that (I hope so)?

I am not sure what you mean by “e steps”, is that simply layer height in Cura? So currently I am printing at 0.25mm, should I try decrease that? What do you mean by decreasing e steps by 1%

Would another material like PLA perhaps give a better result?

Lastly, if the pattern was uniform it would be better, is there a way to control that layer so the extruder head only lays down that layer in one uniform direction?

Apologies for the multitude of questions :smiley:

The top surface looks okay in the pictures… Can’t zoom in to provide further feedback.

What material and layer height are you printing? A smaller layer height could create a smoother top surface. Its going to increase print times… for fast prototyping, the layer height you’re printing looks good.

When you run your finger across the surface is it rough where the infill meets the perimeter? If the surface feels rough, try decreasing flow rate by 3-5%.

Thanks, I am using ABS, with a layer height of 0.25mm.

I am not worried about print time, more quality of finish. If I have to take longer to print it I can live with that. So I guess I should have said, what settings can /should I try changing to achieve the best quality i can?

I am sorry to be so naive, but I assume to reduce the flow rate I reduce the Flow from the current 100% to try 97%?

Higher res image for you btw, hopefully you can zoom this one up.

For a .25 or .3 layer height, that top surface looks about right… Reduce the flow % to 97 or 95. See if that helps.

Can you post the gcode? I’d like to preview the head movement on that top layer… That diagonal line almost looks like ooze from a movement. To control the ooze, try a .1-.2 more retraction (1.6-1.7). Or try printing a degree or two lower.

Thanks, so going to try a print at 0.1mm layer, 97% flow, and a retraction of 1.6, will see if that improves it at all.

I am going to try to attach the G Code file too (hopefully it works)
BN-000101A-Commodore Trip Comp Guage Plate.gcode (1.15 MB)

OK, thanks all. Much better on 0.1. I tried 97% and also 100% and tbh they were slightly different but neither better than the other.

What I am trying to achieve is to make “production” parts, but in just low volumes that are no where near enough volume to warrant injection molding. Maybe I am dreaming, not sure.

Btw, I have just noticed, as I am getting ready for another print, as the head is heating up the extruder is oozing material but very veryy slowly, I am guessing that is normal?

Based on the questions you ask, the surface quality is realy OK. I have seen a lot worser pictures from guys thinking they producing good prints :wink:
There is room to improve, but then you have to invest some time (and filament) for learning. There is no better way than using Google and read what you can find!
Esteps is the value in the printers firmware how many steps the stepper motors have to do to extrude 1mm of filament. The result is the same when you adopt the flow rate % in cura - I would call the flow rate a valid work around for people who don’t want do dig into the bits and bytes.

Normal. As soon as the nozzle is melting material, it will ooze. Nothing is holding back the liquid material against gravity…

Yep. The ooze is normal. What extrusion temps are you using? The ooze may indicate that the filament you’re printing likes a slightly lower temp… try increments of 2-3C.

Typically if you’re near the printer and preheating the hotend, you can hear when the filament transitions to a molten state. That’s probably not the temp you want to print at, but a few degrees above the initial “crackle” is the start of the working range for comparison to your actual extrusion temp. Hopefully it coincides with the temp specified by the filament manufacturer. I like printing eSUN ABS between 241-245… though its extrudable at ~225.

The diagonal lines on the flange looks to be artifact from the way the slicer choose to print the infill.

The diagonal lines on the top is the toolhead travel on the other layers, and the dots are where the filament is retracting (for the layer change).

Really can’t do much about the filament ooze from toolhead travel, mitigating the ooze is you best chance at reducing the artifact. Could try a 45deg rotation of the part on the build platform. Sometimes obscure things like that help the print…

For really smooth parts, print in ABS and look into acetone vapor smoothing. That should get you very nice looking parts. It can affect small details, but that part looks to be a good candidate for it.

Thanks so much all for the advice, its very much appreciated. So looks like there is a couple of good things to play around with. I didn’t realize changes in extrusion temps of just a couple of degrees an make a difference. So it very much looks like 3D printing is one of those skills you can get up and running quickly but there is much more to it as you delve deeper. I have actually mads up an ABS vapor treating rig and had very good results. Its only that with these parts I don’t want them glossy.

kcchen_00 when you say try printing it at 45 degrees, I assume then I would use Support for it?

Yeah, you’ll get really intimate with your machine. :slight_smile: I’d recommend finding a decent filament manufacturer and sticking with them… each manufacturer/brand may need tweaking of settings like multiplier or temps. eSUN ABS is what I stick with because its relatively cheap, and as a bonus you can get 5lb spools of black.

Regarding rotation of the print, try 45 degrees in the Z-axis… so if the flange edges were parallel with the bed edges, after the rotation it would look like a diamond. See below… (sorry for the bad depiction of your model, it was the only square model I had on hand :slight_smile:)

Ok, I get what you mean, I will give that a try. Very interesting all the little things that make a difference.

As far as I can see, using Cura, the infill on top and bottom layers is alway at 45 degrees to the bed, regardless of the part orientation. If your part has a flat top, one particular direction of infilling may give a better appearance. Parallel to the longest dimension of the part on the final layer is a good starter. See kcchen_00’s pictures (OK, that’s a square example). Infill overlap set to 0 (%) can also help (Cura Expert Settings).
Similarly, the position of the grid fill inside an object seems to be fixed, in relation to the bed, not the outside of an object. If you print several identical objects without a bottom layer, this can be seen underneath. This shouldn’t affect the top surface though.

Is there any reason not to just sand those areas smoother if he can’t tweek his printer enough to get what he needs? I’ve also wondered about using heat to smooth things (either a heat gun, or heat up a small metal plate with a soldering iron or something - though you’d have to figure out something to keep the plate from sticking)

I’ve heard of acetone vapor smoothing with ABS before. Is it also possible to do a wipe with acetone if you just need a specific area treated? If so, do you need any special concentration, or anything special to remove the residual acetone when you are done?

Last question: the school I’m working with prints primarily with HIPS. Can you do vapor smoothing - or wipe smoothing - using Limonene (? not sure if I’m remembering the name correctly) ?