This was inspired by some failures due to wrong temperatures (in PETG) as well as wanting the e-nable hands to be strong.
The results page is https://docs.google.com/spreadsheets/d/ ... 5s/pubhtml – just a few test to start, this should grow as more samples are added. I want to understand the impact of factors such as extrusion temp as well as materials. So far I have just tried some of my “standard temps”, which are close in results.
Please contact me for the form link to add your own tests!
I have been using 5x5x70mm samples printed with 3 layers and no fill. I then record other factors such as material and temperature (you can see all the factors on the above link).; I usually print 5 on a raft to get a statistical sampling. You can test other sizes as long as they break at under 100lbs.
- Samples
- Samples.jpg (37.81 KiB) Viewed 3373 times
Below is a description of my test rig. I intend on publishing the files and instructions. This can be built by anyone for about $35-$40.
I built this rig to break a sample in half pulling on a hanging scale. I pull the sample across bolts mounted 40mm apart.
- Test in progress
- FlexuralTest.jpg (24.83 KiB) Viewed 3373 times
- Sample under test
- BreakingSampleScale.jpg (32.44 KiB) Viewed 3373 times
This Scale has a “peak” read feature – so it will show the maximum pull until reset. There are not a lot of meters that will do this, it is the only one I found for not so much ($28): http://www.amazon.com/dp/B00N1AQVSQ
It is limited to 110 lbs, over that the costs go up quite a bit and it is hard to find the peak feature (also, other things may start to have issues with much more force). I pull on the sample very slowly until it breaks, the scale shows the maximum force.
First I tried a tensile pull test on a 1cm square but it required to much force. Even with a “flexural” (break in half) test I found that a 1cm ABS sample would not break at 100lbs. So, I have gone down to 5mm samples – these are breaking at 10-15lbs. So, I think I will use this size as my standard – 5x5x70 with 3 layers and no fill. I may also try and build a holder for tensile (pulling) tests with a smaller sample, tensile would require more force.
I mounted 2 1/4 inch bolts on a doubled-up electrical box cover and pull it with wire rope connected to a hinge. I mounted a handle on the hinge and a printed part to sturdy the sample and scale hook over the box covers. Both will be uploaded to thingiverse with build instructions.