Definitely printing and building one of these. Thanks for making the design available. I also found all the parts on AliExpress and posted them in the comments on Printables. It came out to $58!
It probably doesn't matter until you get to really high loads, but the item under test is off-center from the axis of the puller. That will likely cause the sled to rotate and bind and give you bad readings. But a simple height adjustment should fix that right up. Great video, Rob
Yep! It mostly straightens itself in those situations. I tested this (off-camera) with loads beyond what the scale can handle and it still works fine. The mechanical side is stronger than what the scale can register.
Nice work. Few suggestions if you plan to improve this work: try to align pulling cylinder of linear actuator with hanging scale (same height). Otherwise you will have some torque resulting unknown friction. Additionally in that case, you can use some D-chain link on both sides of test objects to connect linear acturator and hanging scale. No need for those parts in middle you mentioned that they will wear out. Reminder to viewers to buy a hanging scale which will show the peak of one movement. PLA is strong just don't like constant load, impact and heat. So for this application it is good. Only material which would be better is PC-CF. There are bigger T-nuts, but they are not rotating (you have to slide them form the edge). I suggest those for big load applications, like on side where only two holds the linear actuator. I enjoyed the video. Thx.
I bought all the parts from @thenextlayer Aliexpress links for this tester. Your suggestions for improvements make sense. Before I start printing the parts I think it would be better to modify the design to incorporate your suggestions. First, if I understood correctly, you suggest to make the scale and actuator line up at the same height. That means scale has to sit higher so mount for the scale must be modified or new design must be used. I anyway have to use a different mount since I did not get the same scale. Second, what kind of D-chain links do you suggest? Do you have a link to a picture or even better a specific model to purchase? In this case you suggest to completely get rid off the two "sacrificial" parts and put D-chain link through the holes of the test object to pull and the other side of D-chain link through actuator hole and scale hook? Third, I was going to use ABS for all parts. You think for the scale mount PCCF would be required? I would appreciate the reply. I tried contacting Robert over Printables to get the CAD model to modify the mount for scale but he has not responded yet.
I love the clean construction. I don't really have a use for a tensile strength tester, but I kind of want to build this one just because it looks so cool
Since you already have limit switches in the actuator that will disconnect the motor at the end of travel, you could replace the momentary rocker with a single momentary push button (double pole double throw, just like the rocker and wired just the same, but with no center-off position.) Arranged correctly, the rig will fully extend and stop. Pressing the button will make the rig retract until it hits the other limit switch and stop, or until you let go of the button at which time it would immediately reverse and extend back to the stop again, ie, it would reset itself after each test.
I would recommend trying to settle on one size of test sample, rather than having multiple sizes. It will make it a lot easier to compare all your data directly, and should remove some source of error compared to trying to look at force vs cross-sectional area or something like that.
Hello genius brother of mine , Robert could you please guide me how can I modify your design of tensile strength machine to fatigue testing machine ASTM D7791 ...as a big brother kindly guide
I've watched a couple of your video's & now also subscribed.. Your 'Cool' and very entertaining to watch. I've been thinking, for a while, about buying a budget 3D printer.. but don't know an awful lot about them. Think it would be a lot of fun printing things for projects. I'm learning as I watch your video's and getting entertained at the same time. Double bonus! Keep up the good work Robert :)
For sure! I didn't need anything crazy, just something simple and repeatable. Of course it got a BIT out of hand, but it's still pretty simple compared to the other stuff out there.
Great work Robert this was enjoyable to watch. The only issue is on the ram side your pin is below the height equal to the scale side so the test same isn't level.
How about using a quick locking mechanism for the scale cuz using a screwdriver for six screws everytime is annoying 😅 + how about making the sacrificial pieces out of metal
Why does it need to be removed? The sacrificial pieces COULD be made from metal, but it would increase the cost substantially and the plastic already maxes out the scale.
Easy and effective, though your motor is popping the pieces rather fast. If that scale is doing any sort of 'slow polling' or averaging for accuracy, you very well *could* miss peak events, I'd lower the motor voltage for a few trials, just to see if readings get higher, etc.
I too believe in Wago lever locks! I use them all the time at work, and we even use some DIN rail mountable Wagos for signal distribution in audio systems 😎 lol
I did think about this, but it moves the scale up quite a bit. I've found this seems to max out the force on the scale so I opted for simpler/smaller parts.
@@FryGuy1013 looks like you can also just pull by hand and record the max value -- there's an example on YT with the sample threaded over a screw driver rod 😅 Pull hard, boom
Yea like learning he is a wago fearing man (I seriously do not understand how us North Americans collectively decided we wanted the travesty that wire nuts are).
Ah not made here syndrome (About the comment near the start). I too do this all the time. I really like how reduced to the basics this setup is. Nothing to break or need calibration or troubleshooting and easy to just throw out and make another at the mildest frustration, sign of wear or breakage. I definitely tend to over complicate the crap out of things. Id end up reading USB PD specifications, trying to figure out automation, never getting around to perfecting it if I manage to get it to "bah, it technically works" and wondering how I got there. I will say though, I highly recommend thee get thy some auto wire strippers! You deserve the stress free squeeze without strands to poke you left on the desk. They work for basically every wire within range and I think basically all the non full size combat robotics sizes.
I have MANY wire strippers. The knipex ones are really nice and one of my favorites. I did a whole video on different types of wire strippers, I have them all ;-)
I think a good case for why people use stepper motors for this is that they're easy to control the speed of, and they exert their highest torque at their lowest speed. Since you want tensile testers moving relatively slowly, the torque vs rpm curve of a stepper makes a lot of sense for that application, compared to something like a brushed DC motor that needs to be spinning a lot faster to achieve peak torque. I mean you can fix that with gearboxes so I think either option can work well.
yep, 100% true. However, most linear actuators are using gearboxes to slow them down and are essentially screw-drives too. The problem with steppers is the control; they require some sort of electronics whereas as a brushed DC motor just requires a power supply. it's all about the tradeoffs!
Very cool Robert, look forward to your interpretation of layer adhesion results. Many are hesitant to make any strong assertions based on testing, would love to see some techniques and tricks to increase toughness and strength from the same materials, but with technique increasing robustness.
Adding a low cost variable power supply would to reduce the speed for more consistent results. Great simple tester, I appreciate sharing with your viewers.
How are you going to test speed with those small test coupons? The printer wont be able to accelerate to much of a velocity in that small critical section. Maybe a thin walled tube for high speed adhesion tests?
You never want to test just a single sample, you'd always test in batches of 10. But you're right, you won't be able to accelerate at all. A tube is a good idea though.
I did think about this, but once you add in a screw rod, some bearings, etc, etc, it doesn't save all THAT much in cost. This is assuming the person doesn't have a lot of the parts just sitting around. I did have some screw rod and such, but I envisioned $20 in trips to the hardware store.
I imagine if you really went penny pinching a screw drive n20 motor and some metal wire on a pulley could be cheaper, but I think this is a pretty good balance. If you dont care about time as much I imagine you could chop a third off the price with the usual subjects though to me, Ive started valuing the idea of a project that is finishable in a straight burst a lot more than penny pinching.
@@BeefIngot Eh, an N20 is waaaaay to weak. I don't think that would work. There are other motors out there, a windshield wiper motor would be a good choice. You can get them cheap and they have a fair amount of torque.
@@RobertCowanDIY With sufficient gearing the most weasley motor can move the world.... itll just take a bit. I imagine the worm drives that go at double digits or fewer RPM will have the torque. That being said, it's definitely a "is that worth saving 10 dollars" Edit: Because Im silly I decided to look into it and very roughly estimating based on rated torque (lower than stall), an N20 could probably be good for about 2Kg max with single digit RPMs >1000 ratio worms, so not really there for samples of this size, but for smaller ones it could work. I don't know why I bothered looking this up...
Definitely printing and building one of these. Thanks for making the design available. I also found all the parts on AliExpress and posted them in the comments on Printables. It came out to $58!
Thanks! And for people that don't want to wait for ever, you can just use the amazon affiliate links I provided.
It probably doesn't matter until you get to really high loads, but the item under test is off-center from the axis of the puller. That will likely cause the sled to rotate and bind and give you bad readings. But a simple height adjustment should fix that right up. Great video, Rob
Yep! It mostly straightens itself in those situations. I tested this (off-camera) with loads beyond what the scale can handle and it still works fine. The mechanical side is stronger than what the scale can register.
Hey!! I need to make my own Breaking Machine - I wanna play too! 😜
Nice work. Few suggestions if you plan to improve this work: try to align pulling cylinder of linear actuator with hanging scale (same height). Otherwise you will have some torque resulting unknown friction. Additionally in that case, you can use some D-chain link on both sides of test objects to connect linear acturator and hanging scale. No need for those parts in middle you mentioned that they will wear out.
Reminder to viewers to buy a hanging scale which will show the peak of one movement. PLA is strong just don't like constant load, impact and heat. So for this application it is good. Only material which would be better is PC-CF. There are bigger T-nuts, but they are not rotating (you have to slide them form the edge). I suggest those for big load applications, like on side where only two holds the linear actuator. I enjoyed the video. Thx.
I had a feeling that I will see you there Igor 😂! Definitely gonna be inspired by this design for my application!
I bought all the parts from @thenextlayer Aliexpress links for this tester. Your suggestions for improvements make sense. Before I start printing the parts I think it would be better to modify the design to incorporate your suggestions.
First, if I understood correctly, you suggest to make the scale and actuator line up at the same height. That means scale has to sit higher so mount for the scale must be modified or new design must be used. I anyway have to use a different mount since I did not get the same scale.
Second, what kind of D-chain links do you suggest? Do you have a link to a picture or even better a specific model to purchase? In this case you suggest to completely get rid off the two "sacrificial" parts and put D-chain link through the holes of the test object to pull and the other side of D-chain link through actuator hole and scale hook?
Third, I was going to use ABS for all parts. You think for the scale mount PCCF would be required?
I would appreciate the reply. I tried contacting Robert over Printables to get the CAD model to modify the mount for scale but he has not responded yet.
I love the clean construction. I don't really have a use for a tensile strength tester, but I kind of want to build this one just because it looks so cool
Since you already have limit switches in the actuator that will disconnect the motor at the end of travel, you could replace the momentary rocker with a single momentary push button (double pole double throw, just like the rocker and wired just the same, but with no center-off position.) Arranged correctly, the rig will fully extend and stop. Pressing the button will make the rig retract until it hits the other limit switch and stop, or until you let go of the button at which time it would immediately reverse and extend back to the stop again, ie, it would reset itself after each test.
This sounds completely reasonable but I somehow fear a pinch trap is stored somewhere in that suggestion.
That's awesome. I like the simplicity from the design.
I would recommend trying to settle on one size of test sample, rather than having multiple sizes. It will make it a lot easier to compare all your data directly, and should remove some source of error compared to trying to look at force vs cross-sectional area or something like that.
Oh, I will absolutely do that. I just need to land on the perfect size that works for everything.
Hello genius brother of mine , Robert could you please guide me how can I modify your design of tensile strength machine to fatigue testing machine ASTM D7791 ...as a big brother kindly guide
I've watched a couple of your video's & now also subscribed.. Your 'Cool' and very entertaining to watch. I've been thinking, for a while, about buying a budget 3D printer.. but don't know an awful lot about them. Think it would be a lot of fun printing things for projects. I'm learning as I watch your video's and getting entertained at the same time. Double bonus!
Keep up the good work Robert :)
Really love how compact it is. Super handy for testing different filaments when switching suppliers.
For sure! I didn't need anything crazy, just something simple and repeatable. Of course it got a BIT out of hand, but it's still pretty simple compared to the other stuff out there.
I really like your design goals, simple, cheap and accurate. You did great job on balancing them.
thanks!
Great work Robert this was enjoyable to watch. The only issue is on the ram side your pin is below the height equal to the scale side so the test same isn't level.
I thought youtubers could only release modular things... Still, very cool, should be useful.
Haha, right? I'll make a gridfinity mount for it next week.
Video posted 13min ago? Damn. I'm late.
Haha, better watch it a few more times just in case.
I like the design. Nice and simple.
How about using a quick locking mechanism for the scale cuz using a screwdriver for six screws everytime is annoying 😅 + how about making the sacrificial pieces out of metal
Why does it need to be removed? The sacrificial pieces COULD be made from metal, but it would increase the cost substantially and the plastic already maxes out the scale.
excellent job Robert
thanks!
Easy and effective, though your motor is popping the pieces rather fast. If that scale is doing any sort of 'slow polling' or averaging for accuracy, you very well *could* miss peak events, I'd lower the motor voltage for a few trials, just to see if readings get higher, etc.
Yeah, that's a fair point. I'm hoping that the scale registers a max fast enough.
I too believe in Wago lever locks! I use them all the time at work, and we even use some DIN rail mountable Wagos for signal distribution in audio systems 😎 lol
oh nice! Yeah, we use a few wago products at work too.
3d printing is a drug 😅
Efficiency maxxing done proper. Excellent work!
Thank you!
Why didn't you try to position the pins in line with the cylinder of the linear actuator, so that plastic part isn't being twisted?
I did think about this, but it moves the scale up quite a bit. I've found this seems to max out the force on the scale so I opted for simpler/smaller parts.
Great job on a rare tool build. We shared this video on our homemade tool forum last week 😎
I hear simple and think bucket of sand and a scale -- does that mean I'm dumb? 😂
haha, not at all. that COULD work, but it would take forever.
@@RobertCowanDIY Very slick setup Sir!! I might build a similar rig. Any advice on simplest methods for adding displacement/load readouts?
Yeah that's exactly what I was thinking too lol
@@FryGuy1013 looks like you can also just pull by hand and record the max value -- there's an example on YT with the sample threaded over a screw driver rod 😅 Pull hard, boom
@@literailly that COULD work, but you need to be consistent. Shock loads will produce different values versus pulling slowly.
I learned more about Robert in this video than I even knew I wanted to know, and I’m here for it
HAHA. There's a lot more to tell, trust me. ;-)
Yea like learning he is a wago fearing man (I seriously do not understand how us North Americans collectively decided we wanted the travesty that wire nuts are).
Ah not made here syndrome (About the comment near the start).
I too do this all the time. I really like how reduced to the basics this setup is. Nothing to break or need calibration or troubleshooting and easy to just throw out and make another at the mildest frustration, sign of wear or breakage.
I definitely tend to over complicate the crap out of things. Id end up reading USB PD specifications, trying to figure out automation, never getting around to perfecting it if I manage to get it to "bah, it technically works" and wondering how I got there.
I will say though, I highly recommend thee get thy some auto wire strippers! You deserve the stress free squeeze without strands to poke you left on the desk. They work for basically every wire within range and I think basically all the non full size combat robotics sizes.
I have MANY wire strippers. The knipex ones are really nice and one of my favorites. I did a whole video on different types of wire strippers, I have them all ;-)
I think a good case for why people use stepper motors for this is that they're easy to control the speed of, and they exert their highest torque at their lowest speed. Since you want tensile testers moving relatively slowly, the torque vs rpm curve of a stepper makes a lot of sense for that application, compared to something like a brushed DC motor that needs to be spinning a lot faster to achieve peak torque. I mean you can fix that with gearboxes so I think either option can work well.
yep, 100% true. However, most linear actuators are using gearboxes to slow them down and are essentially screw-drives too. The problem with steppers is the control; they require some sort of electronics whereas as a brushed DC motor just requires a power supply. it's all about the tradeoffs!
Very cool Robert, look forward to your interpretation of layer adhesion results. Many are hesitant to make any strong assertions based on testing, would love to see some techniques and tricks to increase toughness and strength from the same materials, but with technique increasing robustness.
Yeah, I'll be curious to see what I find.
Adding a low cost variable power supply would to reduce the speed for more consistent results. Great simple tester, I appreciate sharing with your viewers.
For sure, I'm going to try slowing it down to see if it's consistent.
How are you going to test speed with those small test coupons? The printer wont be able to accelerate to much of a velocity in that small critical section. Maybe a thin walled tube for high speed adhesion tests?
You never want to test just a single sample, you'd always test in batches of 10. But you're right, you won't be able to accelerate at all. A tube is a good idea though.
Nice job, I do like the simple design and cost considerations. Cheers!
Thanks! 👍
This is so simple, perfect !
It too WAY longer to actually design, but it's easily to download, print and assemble in an afternoon (assuming you have the parts)
Nice work, i only wish it would be cheaper 😅
Now i must find a scale with peek hold Funktion with shipping to Germany
For cheaper you can replace the linear actuator with hand actuated lever.
I did think about this, but once you add in a screw rod, some bearings, etc, etc, it doesn't save all THAT much in cost. This is assuming the person doesn't have a lot of the parts just sitting around. I did have some screw rod and such, but I envisioned $20 in trips to the hardware store.
I imagine if you really went penny pinching a screw drive n20 motor and some metal wire on a pulley could be cheaper, but I think this is a pretty good balance.
If you dont care about time as much I imagine you could chop a third off the price with the usual subjects though to me, Ive started valuing the idea of a project that is finishable in a straight burst a lot more than penny pinching.
@@BeefIngot Eh, an N20 is waaaaay to weak. I don't think that would work. There are other motors out there, a windshield wiper motor would be a good choice. You can get them cheap and they have a fair amount of torque.
@@RobertCowanDIY With sufficient gearing the most weasley motor can move the world.... itll just take a bit.
I imagine the worm drives that go at double digits or fewer RPM will have the torque. That being said, it's definitely a "is that worth saving 10 dollars"
Edit: Because Im silly I decided to look into it and very roughly estimating based on rated torque (lower than stall), an N20 could probably be good for about 2Kg max with single digit RPMs >1000 ratio worms, so not really there for samples of this size, but for smaller ones it could work.
I don't know why I bothered looking this up...