mechanical testing for voron-printed parts.

[estoylopez]

Dear colleagues,

I am a mechanical engineer working for a company that makes mechanical testing machines and a 3d printer user also. In my free time, I am building a voron because I don't have a good working order printer any more and instead of buying one I prefer to build my own.
At the same time, I am looking for examples to test in a mechanical testing machine, to make tensile tests to characterize different materials under differents printing conditions (temp, speed,printer etc....)
Therefore, I am asking if there are some people interested in this project to grow the voron community in making a characterization of different materials under different printing conditions using voron printers.
My idea is if people can send me these examples under a specified standard in different printed conditions and different materials and I can make the testings to upload all this information to the voron web. All this data is very useful for engineers who want to print parts to make real use of them in different projects.

I hope this post is clear and easy to understand. Do not hesitate to ask any questions or clarification.

Looking forward hearing from all of you.

 

[Dave32]

Check out CNC Kitchen on YouTube, and I think you will find that this has already been done...

 

[estoylopez]

The

Check out CNC Kitchen on YouTube, and I think you will find that this has already been done

 

[estoylopez]

They have something and they have really good jobs there. But I have in mind to do a reference job for parts printed with voron printers. With this job a designer that want to design something 3d printed will have the possibility to visit this documentation to know how to print the part (temperature, speed, material, position, infill, nozzle diameter) There are a million of possibilities to test, that is why I am asking for help, I will never finish doing it by myself.The goal of my project is to make a characterization of different materials printed with voron following the standard ASTM D638.
The following link is an example of what I am thinking of doing. I hope is ok to put the link I have put here. Is the project I started to do a long time ago.

 

[ChrisA]

Check out CNC Kitchen on YouTube, and I think you will find that this has already been done...

His testing is entertaining, but not so useful. What I'd like to see is data that I can use for design work.

 

[ChrisA]

Dear colleagues,

I am a mechanical engineer working for a company that makes mechanical testing machines and a 3d printer user also. In my free time, I am building a voron because I don't have a good working order printer any more and instead of buying one I prefer to build my own.
At the same time, I am looking for examples to test in a mechanical testing machine, to make tensile tests to characterize different materials under differents printing conditions (temp, speed,printer etc....)
Therefore, I am asking if there are some people interested in this project to grow the voron community in making a characterization of different materials under different printing conditions using voron printers.
My idea is if people can send me these examples under a specified standard in different printed conditions and different materials and I can make the testings to upload all this information to the voron web. All this data is very useful for engineers who want to print parts to make real use of them in different projects.

I hope this post is clear and easy to understand. Do not hesitate to ask any questions or clarification.

Looking forward hearing from all of you.

The problem I have is that

1) The Finite element software I can access does not consider the way 3D parts are made. Printed parts are shells with infill inside. They are not homogenous solids like a CNC aluminum part and the infill can have different patterns and densities.

2) The printed part will have different properties in each direction. It is a little like designing with wood.

3) tiny variations in the process or the brand of plastic filament make a huge difference in the mechanical properties of the finished part. How can you take this into consideration?

I would REALLY like to be able to design a 3D printed part based on requirements but it is way too hard to model so we just design by eyeball and guess and if it does not work gauss again. Because of 1, 2, and 3 above I doubt there can be a better way.

As an example, let's say I print the same G-code twice in my printer. They will not be NOT identical parts because the printer is "more heat soaked" and more warmed up and likely has higher chamber temperature. this is the nature of 3D printing. We don't make hundreds of the same parts, So each is different.

But if you could turn 3D printing into more of a science than a craft, you'd be a hero.

 

[estoylopez]

The problem I have is that

1) The Finite element software I can access does not consider the way 3D parts are made. Printed parts are shells with infill inside. They are not homogenous solids like a CNC aluminum part and the infill can have different patterns and densities.

2) The printed part will have different properties in each direction. It is a little like designing with wood.

3) tiny variations in the process or the brand of plastic filament make a huge difference in the mechanical properties of the finished part. How can you take this into consideration?

I would REALLY like to be able to design a 3D printed part based on requirements but it is way too hard to model so we just design by eyeball and guess and if it does not work gauss again. Because of 1, 2, and 3 above I doubt there can be a better way.

As an example, let's say I print the same G-code twice in my printer. They will not be NOT identical parts because the printer is "more heat soaked" and more warmed up and likely has higher chamber temperature. this is the nature of 3D printing. We don't make hundreds of the same parts, So each is different.

But if you could turn 3D printing into more of a science than a craft, you'd be a hero.

Hi CrisA, Thanks for your very interesting reply. Of your points are exactly the things we need to work out but this is not a simple job this is a long and tedious job that a community can do.

My ideas about your questions are as follow:

1) At present software doesn't take into consideration 3d printing because is too difficult to know all the voids in a 3d printed part. To deal with this point we can use voron 3d printer only to find out how good are these printers at printing the parts.

2) Exactly, The printed parts are not isotropic that is why we will need to specify in the test the direction of how the part has been printed to know the mechanical properties of the part to print in that direction printed.

3) Similar to point 2, We need to specify in the test all of these tiny variations, which is why all the standards are difficult to read, to understand, while other manufacturing process has the same problem. For example, I have discovered that a 3d print part is stronger if it is printed with a thinner nozzle.

The goal of this project is to start to build a table with all of this data. yield stress, UTS, plastic deformation etc..... giving all the manufacturer information of the example to test (position how it has been printed vertically, horizontally, nozzle size, temperature, infill etc.....

I propose that interested people in this project send me 10 or 20 examples or maybe more with information on how the part has been printed, and I will start to test all these parts in a tensile direction to start to build this data.

These data will be uploaded on this web and every designer with the need of it can check it in here. These data have to follow the recommended standards to make a reliable job. I have been looking for a reliable table about 3d printing data and I have not found any so, why not to start to build one.

Looking forward hearing from you

 

[mkl]

Hey, I like this idea, but:

Can you test, how it will perform (or creep) under realistic long-term conditions?

I mean, one of the biggest issues with plastics (imho) is creeping and not the properties i could find in the common datasheets.

The chamber of my V0 gets over 70°C (measured in the back at the cables) and ABS/ASA on the toolhead would fail quickly. Until now I can only try, what could work better and also be printed with it.

Nylon, for example, should resist the heat, but maybe creeps too much over time.

To which country should the samples be sent to?

 

[estoylopez]

Hey, I like this idea, but:

Can you test, how it will perform (or creep) under realistic long-term conditions?

I mean, one of the biggest issues with plastics (imho) is creeping and not the properties i could find in the common datasheets.

The chamber of my V0 gets over 70°C (measured in the back at the cables) and ABS/ASA on the toolhead would fail quickly. Until now I can only try, what could work better and also be printed with it.

Nylon, for example, should resist the heat, but maybe creeps too much over time.

To which country should the samples be sent to?

Hi mkl,

Thanks for your reply. Creep testing is a bit more difficult because more expensive equipment is needed. I guess you can use the material glass point to sort out your problem within the tool head. At the moment I have access to tensile and compression test only,

After reading your reply, fatigue testing came to my mind as an interesting test to do but as well it is a bit more difficult to test so, we can start to do a tensile and maybe compression test to start with the project and start to compare and understand what is happening in a 3d printed voron example.

Nylon is a very interesting material to use for toolhead but it is very difficult to print due to its hygroscopicity. It can be tested in tensile test to figure out its plastic and elastic region at room temperature and to compare with another manufacturing process as injection moulded.

The samples have to be sent to Spain. If you are interested I will give you the exact address and we can start to work. I will book a slot to work with the testing machines in my company and we will be in contact online to make the data table to start to discuss the results maybe in a video call.

 

[mkl]

On most of the voron parts tensile strength isn´t very important, as long as the layer adhesion doesn´t get too bad (like the ABS+ stuff
).

Furthermore some materials even creep at room temperature. See CNC-kitchen´s build of his Voron 0 a few years ago

I got the same experience with Fillamentum ASA, it was just too soft.

PC-CF COULD be brittle and break, I´m going to test some different filaments of that.

 

[estoylopez]

How do you want to test them?

 

[mkl]

I print some parts for my V0 (toolhead) and use it

 

[Dave32]

The goal of this project is to start to build a table with all of this data. yield stress, UTS, plastic deformation etc..... giving all the manufacturer information of the example to test (position how it has been printed vertically, horizontally, nozzle size, temperature, infill etc.....

I propose that interested people in this project send me 10 or 20 examples or maybe more with information on how the part has been printed, and I will start to test all these parts in a tensile direction to start to build this data.

You can certainly do this empirically, but there are so many caveats...

It's an n-dimensional table, with countless variables and tunable factors at play. Crowdsourcing the printing only makes it worse, because you add variances between samples.
For example, If you (as one person) use the same exact printer, same roll of the same filament, sliced with the same slicer and settings, printed at the same temperatures, on the same build plate, at the same ambient temp and humidity.... then your 10 tests for infill percentage variances are comparable with each other.

But if you try to compare across printers, with all of us having different nozzles, print temps (including thermistor differences and PID tuning effects), ambient temps, flow rate calibrations, retraction differences, calibration-related dimensional differences, etc... you're just filling the dataset with variance. Even if we both buy the same filament from the same manufacturer, batch differences can change the results... let alone if we use different colors, where the additives themselves have changed the material properties.

 

[estoylopez]

You can certainly do this empirically, but there are so many caveats...

It's an n-dimensional table, with countless variables and tunable factors at play. Crowdsourcing the printing only makes it worse, because you add variances between samples.
For example, If you (as one person) use the same exact printer, same roll of the same filament, sliced with the same slicer and settings, printed at the same temperatures, on the same build plate, at the same ambient temp and humidity.... then your 10 tests for infill percentage variances are comparable with each other.

But if you try to compare across printers, with all of us having different nozzles, print temps (including thermistor differences and PID tuning effects), ambient temps, flow rate calibrations, retraction differences, calibration-related dimensional differences, etc... you're just filling the dataset with variance. Even if we both buy the same filament from the same manufacturer, batch differences can change the results... let alone if we use different colors, where the additives themselves have changed the material properties.

Agree with your reply but I think that would be nice if we could check how different are the mechanical properties between different settings. For example, Is there a big difference in yield stress between different setting configurations?
That is why I am looking for a big 3d printing community. I would like to have a lot of different samples to test, with different configurations so all of us start to see all of these data on graphs.
I think that the data we can get from this project can be very interesting for all of us.

If the community is interested in this project I will need as many examples as I can to test them with different configurations and materials with the examples dimensions attached.

 

[TheMan]

Hi CrisA, Thanks for your very interesting reply. Of your points are exactly the things we need to work out but this is not a simple job this is a long and tedious job that a community can do.

My ideas about your questions are as follow:

1) At present software doesn't take into consideration 3d printing because is too difficult to know all the voids in a 3d printed part. To deal with this point we can use voron 3d printer only to find out how good are these printers at printing the parts.

2) Exactly, The printed parts are not isotropic that is why we will need to specify in the test the direction of how the part has been printed to know the mechanical properties of the part to print in that direction printed.

3) Similar to point 2, We need to specify in the test all of these tiny variations, which is why all the standards are difficult to read, to understand, while other manufacturing process has the same problem. For example, I have discovered that a 3d print part is stronger if it is printed with a thinner nozzle.

The goal of this project is to start to build a table with all of this data. yield stress, UTS, plastic deformation etc..... giving all the manufacturer information of the example to test (position how it has been printed vertically, horizontally, nozzle size, temperature, infill etc.....

I propose that interested people in this project send me 10 or 20 examples or maybe more with information on how the part has been printed, and I will start to test all these parts in a tensile direction to start to build this data.

These data will be uploaded on this web and every designer with the need of it can check it in here. These data have to follow the recommended standards to make a reliable job. I have been looking for a reliable table about 3d printing data and I have not found any so, why not to start to build one.

Looking forward hearing from you

That does sound like something useful, especially for people like me that like to try out different approaches in an effort to improve upon a commonly accepted method which no one knows why it was adopted. Most likely, simpler infills can be modeled, but the layer adhesion between layers would still be unknown, as well as the difference of materials from different manufacturers. It would be nice to prove out parts prior to building an entire machine. I just watched a YouTube video by My Tech Fun talking about Creep Testing, I don't know if he's an expert or not or how and where he came up with the approaches shown in the video. I would be willing to donate parts for testing, at this time I wouldn't have the expertise, time or equipment to do testing myself. I have noticed that most part design is done as if they would be machined parts, perhaps because a lot of people have CNC backgrounds, and not like molded plastic parts.

 

[ChrisA]

You can certainly do this empirically, but there are so many caveats...

It's an n-dimensional table, with countless variables and tunable factors at play. Crowdsourcing the printing only makes it worse, because you add variances between samples.
For example, If you (as one person) use the same exact printer, same roll of the same filament, sliced with the same slicer and settings, printed at the same temperatures, on the same build plate, at the same ambient temp and humidity.... then your 10 tests for infill percentage variances are comparable with each other.

But if you try to compare across printers, with all of us having different nozzles, print temps (including thermistor differences and PID tuning effects), ambient temps, flow rate calibrations, retraction differences, calibration-related dimensional differences, etc... you're just filling the dataset with variance. Even if we both buy the same filament from the same manufacturer, batch differences can change the results... let alone if we use different colors, where the additives themselves have changed the material properties.

This variation is a good thing. When you publish the data for say "Young's modulus" for glass-filled PC you will also publish the standard deviation. Then people can read your table and see that the answer is "about 3,000, plus or minus 2,900"

Seriously, this is the result I'd expect from a crowd-sourced sample set. Some people are REALLY bad at 3D printing and some people are really good. We can't use data from either of these groups to do design work. I want to see the spread. Don't bias your data by accepting only the very best work.

 

[pajtaz]

Dear colleagues,

I am a mechanical engineer working for a company that makes mechanical testing machines and a 3d printer user also. In my free time, I am building a voron because I don't have a good working order printer any more and instead of buying one I prefer to build my own.
At the same time, I am looking for examples to test in a mechanical testing machine, to make tensile tests to characterize different materials under differents printing conditions (temp, speed,printer etc....)
Therefore, I am asking if there are some people interested in this project to grow the voron community in making a characterization of different materials under different printing conditions using voron printers.
My idea is if people can send me these examples under a specified standard in different printed conditions and different materials and I can make the testings to upload all this information to the voron web. All this data is very useful for engineers who want to print parts to make real use of them in different projects.

I hope this post is clear and easy to understand. Do not hesitate to ask any questions or clarification.

Looking forward hearing from all of you.

Hi, I am interested in helping out. I print a lot, I am in Europe, have plenty of filament, and I am also an engineer interested in the data that you can collect. How do we get in touch?