is this just my perception or does this printquality bite

Hi folks is it just me or are these prints of poor quality, seems to me like the layer's are not fused right,


and there seems some warping going on what are the things that have been done wrong here since,
I've seen pictures of much better prints I would like your feedback.
Mind you I'm a noob and I bought these parts off eBay.
I want to know what was done wrong here so when I'm up and running I can avoid the same problems.
Any comments would be welcome
terramir
PS I also attached them on the bottom in case they don't load right

Too fast
Too hot (in bridges)
poorly tuned PWOT in solid infill?

... just guessing...


but dimension still OK to put in the bolts 'n bearings.

so I was right the quality is poor, question what is PWOT, others feel free to elaborate.
terramir

The main bracket looks like you printed it standing up, whereas it should be printed lying down of the large flat side.

There shouldn't be any gaps between the solid infill lines. The flow rate is too low for those.

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[www.hydraraptor.blogspot.com]

well I did not print it I got it off eBay I'm asking because I want to learn
terramir

Looks like you've learned a lot already

How not set up your machine
How not to print a wades block
How not to adjust your bed
How not to setup a slicing program
How not to set your temperature
How not to buy parts off Ebay without a good accompanying closeup picture.
That's disgusting. Can you send that puppy back?

hey bruce that's really harsh and unwelcoming.

Terramir: those parts aren't great, but if they look functional, you can always replace them when you get printing. If you can send them back and get all your money, then go ahead.

Bruce Wrote:
-------------------------------------------------------
> Looks like you've learned a lot already
>
> How not set up your machine
> How not to print a wades block
> How not to adjust your bed
> How not to setup a slicing program
> How not to set your temperature
> How not to buy parts off Ebay without a good
> accompanying closeup picture.
> That's disgusting. Can you send that puppy back?


Sure, they are good examples of what NOT to sell on eBay, but unfortunately the OP hasn't learnt anything (except maybe the risks of buying on-line without detailed photos and references from satisfied customers), because he doesn't know any of the settings that were use to create these prints!

To the OP - yes, better quality parts are definitely possible; you could try to contact the supplier to see if they will acknowledge the issue and replace them - but this will probably take some time (especially if they dispute your claims about quality and deny your request for replacements).

Or you could just go ahead and use them and hope for the best. While they are not brilliant, they look like they are probably serviceable, at least for a while. The benefit of this is that you can just go ahead and get your machine working ASAP, with a view to printing your own (better) parts once your machine is running and calibrated. The risk with this approach is that the parts could fail catastrophically early on in your printing trials - but one way or another, you should be able to get replacement parts if / when you need them.

Good luck - keep us posted with how you go!

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Follow my Mendel Prusa build here: [julianh72.blogspot.com]

I know that these parts are not the greatest (well except for the hobbed bolt he got that right on the money if I compare with some pictures, he included spare parts (the idler 2x and the big gear one and 3x small gears spare it was not that much, and I figure after I finish my reprap this is one of the first parts I'm printing after I get it properly calibrated. however what I am really interested in is the physics (not as in formula's but general) behind this failure versus good prints.
#1 I dun get too hot wouldn't that cause less "stringiness" and more bonding together, while killing the overall shape, I would have guessed this was extruding too cold, see what I know.
#2 I figured that the flow rate was not adjusted properly for the speed, i.e. I figured the computer was thinking it was pushing more material than it was.
#3 yes I agree this was printed in the wrong direction as well, but maybe this is what let the guy get it working at all I think his whole set-up is a bit messed up.
#4 I need these parts to get started because the thing is actually gonna be a repstrap until I can print all the parts to make it a proper reprap.
this part is one thing I cannot replicate in wood without spending more time than it's worth. since I have no access to either cnc or a wood cutting laser
I can make the rest somehow and muddle through untill I get it right.
terramir
What I really want is some people to tell me if I get these kind of quality prints what could be possible causes and please make it so a total noob can understand, what should I do to fix it.

Hi terramir,

If you are happy to look at some pictures and read what people have said about them, then you may learn some things in our Art of print failure group on Flickr - it has quite a lot of common issues people face when setting up machines and common print issues, like what a print looks like if you have loose belts, over fill/flow, bad extruder calibration, underpowered motors, etc, etc.

I'm sure those parts will help you get a machine up and running, and while not being great quality you can re-print your own set. It's harder than it looks and takes some time to get a printer set-up well, and many people simply don't know when they start out what good parts look like or how to make them better. - we can all help improve that aspect. - Please join the group and add to the art of print failure when you get your machine up and running, you should have plenty of similar issues, no machine is perfect 1st print!

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[richrap.blogspot.com]

looked at those pictures does give me some ideas what I need to know. got a question about this while parts cool off they contract, in the software we use for printing are the contraction co-efficents pre programed or do we have to program those into our original models just curious because looking at those fail pictures popped that question into my head.
terramir

I can't answer your question about shrinkage, although I don't believe it shrinks that much compared to the accuracy needed.

You really should check out Richrap's and Nophead's blogs. They do very good jobs with testing and tweaking and analyzing the results. Helps you with how the printer works and what to expect. Gary Hodgson also has good information on his blog.

PWOT: Perimeter Width over Thickness ratio. See here
When the filament goes down it doesn't stay round. It is expected to down somewhat flattened. think of how the side of a log cabin looks and the difference between untrimmed logs and ones that have had a bit taken off the top and bottom so they aren't as round as they used to be. You'll get a smoother part if teh layer is wider than it is tall.

It does depend on the material being used and temperature, speed etc. but after a short while you will start to get a feel for how your machine prints. and if you print a normal part that other people use and things don't fit then that may indicate you have a calibration issue.

In Skeinforge the 'Stretch' tab can help you get better fitting parts like HEX nuts in things, but a well calibrated machine will print very close to the model - I tend to give myself 0.3 clearance/tolerance in the model and it prints as I expect.

And I'm always very impressed how repeatable prints are, you can print the same set or thing 10 times and exact copies, right down to the tiny stops and start features in the model or identical infill lines all at exactly the same places, it's amazing.

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[richrap.blogspot.com]