OpenBuilds Actuator Test Rig

Very good. Actual measurements of accuracy, repeatability, max force, and max speed for different actuators. How difficult would it be to include some Rack and Pinion measurements?
On a somewhat related note, has anyone published the flex of various linear rails of common lengths?

 

For the more visually oriented among us (and you know who you are):

 

Nice graphs. I have to ask about the Nema 23 screws, are they ACME or ballscrew? If ballscrew, what diameter/pitch?

 

Interesting. It would be interesting to see the test done with a double belt setup (one into the other). In theory, it should improve at least the repeatability of a single belt setup ...

 

I would love to see that tested too as double belts made a huge difference in cut performance but hard data like yours would blow my mind!

 

I'm not (currently) using the double belt setup having good results with the standard single belt. But as I progress with use of myOX, I'm thinking of extending the Y from 750mm (Vslot length) to at least 1000mm AND going to double belt. I have to stop making free signs ("practice" runs) first.

 

If I can recommend only one upgrade to ANY ox/belt pulley user it would be to double belt it. It makes SUCH a HUGE difference that IMHO should be done on any length axis. The hardest part is finding a good quality double sided tape that can stick to both rubber and the rail. Too thick and you wont get the two belts under the wheels.

 

Dear Rob,

First, thanks for your job and thanks to share it !

It read with interest and attention your two following links :

https://openbuilds.com/uploadfiles/Part Specs/OpenBuilds® Actuator Tests_V2.pdf
OpenBuilds Actuator Test Rig

If there is another document your wrote, I did not find it, and I would be glad if you can transfert it to me (or its link).

It is clear that you know engineering and mathematics, and I do not doubt that you made your tests properly.

Have you done your tests on the ACRO systems currently for sale on openbuilds.com ?

I am concerned by the results you have got : about 0.3 mm for Nema 17 and 0.6 mm for Nema 23 (both for belt driven systems).

I am using a very cheap chinese laser cutter (a "K40", you probably know). I have not done such tests, but for sure the accuracy is much lower (I mean less than 0.3 mm) as I already produced many objects and had no problem to assemble them with very small clearances. It is also highly repeatable : I can assemble pieces with quite not clearance (less than 0.1 mm).

I can't believe neither that my K40 is better than ACRO systems. I would like to buy one ACRO systems but now I feel confused.

Do you have any idea ?

Thanks in advance to answer me,

Best regards,

Fabrice, from France

 

@Ariel Yahni

I have not done evoluated tests like Rob Stehlik, but I produce many identical pieces that I assemble for a very tiny clearance (less than 0.05 mm, measured with a caliper), and all the pieces can be assembled with no problem.

 

I assume the beam width is constant. The beam width has no consequence on the accuracy of the cut.

 

How does it ?

 

How the material can affect the positioning accuracy of the laser head ?

 

Ok, I understand better.

Do you own a K40 ? An OpenBuilds system ?

I am disappointed when you write "K40 is more accurate than openbuilds actuators".

I am searching for a system with the same accuracy than my K40.

 

Sorry, my english is not perfect.

It is a misunderstanding. I though you meant that K40 is more accurate than openbuilds actuators.

According to you, is it clear that an OpenBuilds ACRO System (belt driven) is more accurate than a K40 ?

 

I am sorry, I am not sure I understand your sentence "You need to understand the parts that compose the K40 tu actually find something "better" specially the stepper motors, belt and idler".

Your opinion interests me a lot. Can you explain me what you mean in this sentence ?

 

Ok, thank you, I am confident