[Hollow threads/helix]

Thanks for the link.

Did the upload and repair but for the life of me I can't download the repaired file.

It seems to be a known bug.

Are there any other repair programs?

 

You could also try running your previous model through Netfabb's cloud service and see if that corrects the error in the model:

https://netfabb.azurewebsites.net/

[Hollow threads/helix]

I can answer my own question.

The problem lies with Sketchup. I was trying to make a thread with a circular cross section, changed it to a triangular one and it worked OK.

Cura really does pick out the problems before printing. I don't always trust the 'normal' view but the layers view seems to be 100% correct.

[Hollow threads/helix]

I have just been trying to make a threaded hole.

Using Sketchup, I made the helix on its own, copied and pasted it into the object with the hole, then moved it into position.

When I exported it into Cura everything worked, except that the threads appeared to be hollow, with only the outer shell on them. They seem to stay hollow even when Cura is set to 100% fill.

Any ideas?

Not sure if this is a Cura problem or to do with Sketchup.

[Filament Jam]

The end 50mm of the filament must also be perfectly straight, ( as well as pointed ). The feeder is trying to send the end of the filament into quite a small hole and if it isn't straight it hits the edge instead.

 

Try removing the material out of the machine. If it doesn't come out via change material then turn the machine off and just pull it firmly out.

Cut the filament into a point so it's like a sharpened pencil. Sometimes it can catch on a edge as it enters the nozzle.

try this first as it's the main cause.

[ABS Warping...not solved...]

Reply to Kris :

Try and round the sharp corners of the object, angles increase stress.

Use of 'ABS juice', ( search elsewhere on the web ) is a must to prevent lifting off the bed.

Fans must also be off when using ABS.

I have done all this...corners still come up...but the cover on top of the Printer helped me that there was no cracking on the Layers.

Still trying...

[Z-Axis layer error]

Have you ever lubricated the Z axis slide pillars?

I have just experienced this problem and it was due to lubrication on the pillars. The slides are ball races and need a small amount of friction to rotate. Oil the pillars and they will try and slide, not rotate, causing a jam. I removed all trace of oil and the problem has cleared.

John

 

I've always had an aversion to manually moving such seemingly delicate parts. So I rarely did it. However In my case I just noticed the z-screw moves as if it had sand on it! Especially towards the top. Come to think of it I've only had the z-layer issue since I relubed the screw a few weeks back. I have no idea what went wrong as I used the supplied Magnalube in the way I was told to. But I hope properly cleaning and applying new lubrication will fix my problem.

[Started to get some random, yet extreme, Z artifacts on one of my UM2's]

Have you put any oil onto the Z axis slide pillars?

I would remove it if you have.

See my thread earlier on.

 

Also if your filament varies in diameter by a lot you can get this so try another filament.

[Consistent Variations In Layer Height]

I have had a similar problem, periodic wide layers and have just fixed it.

After a lot of playing around I realised that I had oiled the Z axis slide pillars at the same time as the X & Y rods.

The Z axis bearings are ball races, so if the pillars are lubricated the balls will try and slide rather than rotate. Some slide, some rotate and you get a jam.

I removed all trace of lubricant from the slide pillars and the machine worked perfectly and has done some over about 4 x 4 hour prints. I am routinely wiping the pillars with kleenex before a run.

John

 

Thanks. I think I gave the drive gear a good cleaning and a little grease. So far so good. I appreciate the help.

[Z axis banding again]

I think I have solved it!

The problem was due to the Z axis slider bearings. The pillars should have NO lubrication on them at all. I had put a spot of light oil on them along with the X & Y slides.

I eventually realised that the Z bearings are ball races and lubricating the pillars caused the balls to try and slide rather than rotate. Some slid, some rotated and that is what caused the jamming. After wiping the pillars dry, they began to slide really smoothly. Have done several prints since, all without any of the problem bands.

I eventually got the nut undone but that rotated very smoothly.

thanks

John

 

Sounds as if you're getting closer. It's possible that it's the bearings. Another possibility would be the rods. But the bearings are actually more likely to be the problem. Maybe your printer was hit during shipment? This might be a good point to contact support if you have not yet. Maybe they can send you new bearings.

[Z axis banding again]

Thanks, I have already put a support ticket in.

Unscrewed the 4 bolts on the nut but the nut won't come off, daren't put any more pressure on it.

The rods look clean and true.

When I slid the bearings up and down it felt like loose bits inside them, really rough.

John

 

Sounds as if you're getting closer. It's possible that it's the bearings. Another possibility would be the rods. But the bearings are actually more likely to be the problem. Maybe your printer was hit during shipment? This might be a good point to contact support if you have not yet. Maybe they can send you new bearings.

[Z axis banding again]

I think the problem is the slide bearings though.

I have unscrewed them from the build plate and tried to slide them up and down the pillars. Really very difficult to do, they seize every few centimetres, then work for a while, then seize again. I was expecting very smooth motion on these, occasionally I started to think they had totally jammed. Both of them seem the same.

Is this correct?

 

The bearings are left and right.

The nut is that cheap looking brass piece at the back of the build plate (center). The piece de resistance might be in there as the pattern occurs regularly. Take the whole build plate away and unscrew the nut and clean it thoroughly.

[Z axis banding again]

Is that the bearing at the back on the build plate?

No obvious play on it. One of the four bearing mounting screws was loose, tightening it hasn't made any difference, ( the other 3 were tight ).

 

What about the nut? Does it have play on the thread?

[Z axis banding again]

I have done a complete clean of the lead screw, wiped off all the grease from the threads and re-greased. Slides a treat, the build plate almost falls by itself under gravity.

However, around the area in question, 10-25mm down, there is some friction which appears periodically. At the same time, I can sometimes hear a faint grinding sound from around the bearing/slide area. The sound isn't from down below where the motor is. The lead screw looks perfect, no signs of any imperfections at all, so I am wondering if there is a problem with the slide bearings. The slide pillars look perfect, no marks on them and are lubricated OK.

Hope this isn't a duplicate, I posted it about 30 mins ago and it didn't appear.

John

 

I usually use a piece of cloth and a spray for de-greasing e.g. bicycle chains. Afterwards you should quickly put grease or oil on it (I use a special chain oil).

[Z axis banding again]

Ah, no! Will try that.

Any ideas for a tool to help?

 

Did you clean the z axis before re-lubricating?

[Suspect some charring using white ABS]

Thanks, sorry I didn't respond sooner.

I've changed to PLA and am getting the same charred bits. It isn't from the outside as I keep the nozzle pretty clean but I now see them fairly frequently at the start of a print, they usually are all out by the time it has printed the brim. They seem to build up within the nozzle and are disturbed when the nozzle cools down and heats back up again.

I've started to do a dummy print in the same run before any important ones in order to get hem out.

 

Hi John,

I sometimes get small inclusions of dark char like deposits within a white print. Whenever I've watched this happening it's source has been the outside of the nozzle and not from within.

Check the nozzle surface is clean before starting a print. Any small pieces of filament that are stuck to the outside can release after its gone through a few heating and cooling cycles which then get embedded in the print.

This is far more noticeable on a white print due to the contrast.

[Z axis banding again]

I would like some more ideas on this Z axis banding issue

These bands cause total delamitation in ABS but are not fatal in PLA.

It isn't a feed issue, as the bands occur on both the arms of the object and there has been a retraction between each arm. I am also using the PLA on a coil, not a spool, so the filament is not tightly wound.

It really looks like a Z travel problem. I have re-lubricated the lead screw and when I pull the build plate up and down there are no obvious tight spots of high friction. However, the problem does tend to occur in the same region each time between 8mm and 20mm from the base, never below 8mm and rarely above 25mm. The position is random, I can build the same object with the same file and the bands can move about and vary in number. The Cura file X-ray is clean.

Other people seem to see the same or similar problem but I can't see any fix which has nailed the problem.

Any ideas would be greatly appreciated.

John Fox

[Delamination and Z axis movement]

I think I have fixed it!

I suspect the problem is a mix of the ABS (with high warping ) and my design. The object had several right angle corners and I think these create a lot of stress which caused explosive de-lamitation across a whole layer. I have redesigned the item with radius curves on most of the corners and the latest print was fine.

thanks

 

Just had another 'event'.

About 10mm vertical height printed perfectly, then one whole layer incorrect with quite an obvious gap all the way round, subsequent layers then OK until I aborted the print.

Spool is OK, extrusion of all the layer seem OK, what is happening occurs to a single layer only.

John Fox

 

Which printer do you have?  Please update your profile settings to indicate this.  Also update your country/location as advice changes often depending on the country.

What you describe can happen but usually if there is a layer like this it can also be caused by underextrusion due to temporary tangling filament, temporary cold layer (often due to fans coming on) and similar things like that.

 

[Delamination and Z axis movement]

Just had another 'event'.

About 10mm vertical height printed perfectly, then one whole layer incorrect with quite an obvious gap all the way round, subsequent layers then OK until I aborted the print.

Spool is OK, extrusion of all the layer seem OK, what is happening occurs to a single layer only.

John Fox

 

Which printer do you have?  Please update your profile settings to indicate this.  Also update your country/location as advice changes often depending on the country.

What you describe can happen but usually if there is a layer like this it can also be caused by underextrusion due to temporary tangling filament, temporary cold layer (often due to fans coming on) and similar things like that.

[Suspect some charring using white ABS]

I am using white ABS supplied by 3D Prima, running on an UM2 at default temperature settings of 260C. From time to time I get brown colouration on the bottom two or three layers. I suspect that this is due to the ABS starting to char.

Is it worth trying to drop the temperature at bit or will this lead to other problems?

Oddly, this doesn't seem to occur elsewhere on the print.

thanks

John

[Delamination and Z axis movement]

Just done the profile - forgot about it.

I certainly have had problems in under extrusion, (something in the nozzle), that seems to have cleared now.

I am about half way through a spool of filament, is it necessary to try and uncoil it? It seems to be quite highly coiled as it nears the centre.

John

Which printer do you have?  Please update your profile settings to indicate this.  Also update your country/location as advice changes often depending on the country.

What you describe can happen but usually if there is a layer like this it can also be caused by underextrusion due to temporary tangling filament, temporary cold layer (often due to fans coming on) and similar things like that.

[Delamination and Z axis movement]

Hello,

I am attempting to print some small geometric shapes, typical dimensions are 60mm x 40mm on the X & Y and 30mm on the Z axis.

Periodically and at random, I am seeing what appears to be the Z axis travel to be more than the set amount. Current setting is 0.1mm and I suspect the drop on the build plate to be around 0.15 - 0.20mm when the problem is seen. This causes an obvious band all the way round the print, which in some cases starts a delamitation. When I peel the object apart at the fault, I can see that the walls have not fused to the layer below, implying a greater than normal Z axis shift.

The problem bands occur once or twice per print and always show all the way around the print with the next layers looking perfectly normal.

The printer is only 2 weeks old, seems to perform perfectly apart from this. I am using ABS.

Any ideas?

thanks in advance

John Fox