[3D Printing Tubes and Supports]

 

 

 

 

 

 

 

5

On 4/15/2019 at 6:44 AM, geert_2 said:

You could try printing a short, straight section of a round tube sideways, for test. Print rather cold, and with max fan, or even with an additional desktop fan in front for fast cooling. The roof-section of the inside might look a bit like it has grapes hanging from the ceiling, but the canals should stay open. Try the concept on a short straight test piece first, to see how much the inner roof sags, and if this is still acceptable for you. PLA can usually bridge gaps quite well.

 

This is a test of a table model, with custom support structure. At the underside of the support structure, you see how much it sagged. The middle section overhang is 30mm long. But you can do better by printing colder.

 

So, if such an amount of sagging would still be acceptable to you, you can print it without internal supports.

 

The external part will need supports and good brim, otherwise it will fall over while printing. So you might consider some support structure similar to the pink support in the blue spring, and then cut that out later.

 

 

 

 

 

 

I found an ok solution: I twisted some steel wire into a small cable using a power drill, and simply pushed that through the tube, making sure to twist it and break up the supports inside. However, I am still seeking a better solution. I will be sure to print out some smaller "test tubes" with different support settings and share the results.

[3D Printing Tubes and Supports]

On 4/8/2019 at 8:13 AM, geert_2 said:

Does it have to be a circular tube? Or would a pentagon-shape also be okay? Or a triangle on top of a square, like a house-symbol? In that case, you could print it sideways, with the flat area towards the bottom, and the "roof" on top. I will try to insert a unicode symbol here, if the system allows it: ⌂

 

On 4/8/2019 at 12:59 AM, kmanstudios said:

Dual extrusion with PVA supports?

Sorry for the late reply. I don't have a dual extrusion printer, so that can't be an option for me. It would also be a pain to go back into the model and change all of my tubes into a different shape, but I will consider it. Any more ideas? All I've been able to think of was maybe creating some kind of tool that can reach in the tube and remove the supports.

[3D Printing Tubes and Supports]

I was wondering if anyone could provide any tips or guidance when it comes to 3d printing tubes with supports. When designing the tubes, I quickly realized that they would have to print with supports inside them. I understand that it is easy to print tubes without supports if they are just straight, but if the tube includes curves, bends, twists, etc., how exactly would you remove them?  

 

Here's a curved tube that I need to print:

 

Supports would need to be created inside the tube toward the bottom, but how could I remove them once the print is completed?

 

[Best Support Pattern for removing?]

Thanks for the help! Would the gaps between the supports just be however long you think your printer can bridge?

[Best Support Pattern for removing?]

Does anyone know the best support pattern for removal? I am attempting to print a small spring so I need something that can be removed without breaking the spring. 

[Calibrating Extruder on Ender 3]

I have been having problems calibrating the extruder on my Creality Ender 3 printer. According to this webpage(https://mattshub.com/2017/04/19/extruder-calibration/), you must measure 120mm of filament from the extruder and mark it, extrude 100mm of filament, multiply the current steps per mm value by 100 and divide it by how much filament was actually extruded to get the new steps per mm value. I tried this, and say if I had 20.5 mm of filament left and did the aforementioned steps, my value would end up overshooting it, and I would next end up with 19.5mm left. I don't know what the problem is, as I have checked and my extruder gear and it seems to be working properly and not slipping. It could be that I am not measuring the filament in the exact same spot each time, and if so, how do I? I am overall goal is to achieve a printing tolerance of 0.3 mm, as my printer has barely gotten a 0.5mm on a tolerance test and nothing more than that. I have also tried printing cool, unifying speeds, and controlling acceleration. Any ideas?

[Tolerance Issues]

16 hours ago, Smithy said:

Hi

 

here are some advises which helps a lot to get a better dimensional accuracy and tolerances:

 

Print slow
The slower the printing, the more positive the effect on dimensional accuracy. Ideally, you should print between 25-45mm/sec.

 

Print cool
The best results are obtained by printing as cold as possible. One way to find the right printing temperature would be to reduce the temperature until you see under extrusion and then raise it 5-10° again.

 

Unify speeds
One of the most important rules is to set all speeds in Cura to the same value. Cura usually calculates the print speeds according to a specific formula. Infill, for example, prints much faster than an outer wall. Due to the permanent acceleration and deceleration, a certain under or over extrusion always occurs, which in turn negatively influences our dimensional accuracy. 

 

Acceleration & jerk control
Acceleration and Jerk Control decelerate the print head before and accelerate it after a change of direction so that less vibration occurs when printing e.g. a 90° corner. However, as with the different speeds, over- or under-extrusion can also occur. This can be seen very clearly at a 90° corner, which is then slightly bulged outwards. For dimensionally accurate prints, the two options should, therefore, be switched off.

But there is also a disadvantage because if the print head then goes around the corner unbraked, vibrations arise which then show up through so-called ringing on the surface. But this ringing is only optically visible and not really measurable. So for technical parts, where the surface is not important, but the dimensional accuracy, Acceleration and Jerk Control should still be switched off.

You have to find a balance between ringing and dimensional accuracy. If the surface quality is important, the values for Acceleration & Jerk Control can be adjusted to obtain a good balance.

 

Elephant foot
The so-called elephant foot is created on the first layer, where the material is pressed into the print-bed to achieve optimum adhesion. This also displaces the material and creates a lateral bulge. The object is then slightly thicker on the underside than in other places.

The "Initial Layer Horizontal Expansion" option can be used to adjust this behavior. Common values would be -0.2 or -0-3 mm depending on nozzle diameter.

Ok, I've tried all of the recommended methods but I still can't even get a 0.3mm gap on a tolerance test. Do I need to further calibrate until it's perfect? Could there be something wrong with my printer?

[Tolerance Issues]

Thanks for the advice. I’ll update you when I’ve tried that.

Edit: One question, should ALL of the speeds match? There seem to be a lot of values(travel speed, initial layer speed, top/bottom speed, etc.).

[Tolerance Issues]

Hi, 

I'm quite new to 3d printing, and am having issues with gap tolerance on my new Ender 3. I doubt it is the printer, as I have it calibrated down to a 0.02 mm inaccuracy on 20mm test cubes on the x and y axes. Despite this, I can only get the .5 mm gap to work on various tolerance tests with the help of a screw driver. I have also had issues like holes being too small, and certain parts not fitting together well. I am using Hatchbox PLA filament at 205 degrees on the nozzle and 60 degrees on the bed. I am using the recommended settings on cura except with zhop and combing on all.