delrin balls anyone?

hi all my first post here, im quite a nube to 3d printing, the last few mths ive been building a semiU 3dr and getting it printing successfully ive found i really do enjoy these machines, but it needed a mod or 2 to get it how i wanted. I have put a new effector assy and heat bed and ive transformed my 3dr in to a fine delta machine that now will hold its calibration and has more build area.

Anyway i just wanted to see if anyone else has used these delrin balls im using? i got them from here if you havent seen them before they make this mod so much simpler.

so for the new ball and spring effector mod, i got the effector and carriages from here and the guy made me a 8mm smooth rod version which was very good of him (there is a 6mm smooth rod version as well)
Ive used 4mm solid carbon rods press fitted into 9mm delrin balls (i gave up trying to drill stainless balls) ive not seen anyone else using delrin balls and they have so far proved to be very good and i dont see that changing, they are light weight and self lubricating and seem to me to be a good way to go (and so much easier to drill ) I drilled them with 4mm blind holes and pressed them on to my carbon rods no need for glue which is always a bonus, balls on rods are a very clean looking solution i think, and i used 3 thin 6cm springs i had in a box of mixed springs from maplins and a made braid loops to attach to the springs and hold it all together. ive also fitted a heated bed now and stated printing on glass which i find much simpler and no more blue tape i have been using a pva wash to great effect,

Anyway hopefully someone might find the delrin balls a good solution for them. the mod has made my delta so much better not a bit of backlash now! and if i have one of these Duh! moments when the nozzle hits glass the rods will pop out saving my delta from any damage.

This looks a great forum and i hope to become a useful member in the future.

Kind regards Forest

Sorry pics are not the best quality

It sounds like a good alternative to magnets for heated enclosures.

Do you have the specifications for the spherical tolerances?

Edited 1 time(s). Last edit at 12/30/2015 02:21AM by etfrench.

The hardest part will be to drill them 100% centered. Compared to Traxxas or other rod ends, it's another hurdle.
A bit off center and your effector will tilt in any direction.

Let's see if some one comes up with a professional rod-kit ( hint, hint )
-Olaf

Reading the title of this thread the 1st sentence comes into my mind by "No Sir, I don't have Derlin Balls" ...

Quote
o_lampe
The hardest part will be to drill them 100% centered. Compared to Traxxas or other rod ends, it's another hurdle.
A bit off center and your effector will tilt in any direction.

Let's see if some one comes up with a professional rod-kit ( hint, hint )
-Olaf

If it were me I'd design and print up a jig to both clamp the ball, and centre the drill.

Wouldn't be hard to design something like that, just a cube with a spherical cutout in the middle, with a hole for the drill and the whole thing split down the middle.

When you press fit the rods into the balls how do you ensure that you end up with identical lengths in the rod/ball assemblies?

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hi guys thanks for your comments

Quote
etfrench
It sounds like a good alternative to magnets for heated enclosures.

Do you have the specifications for the spherical tolerances?

there is this tech data for them

ISO Symbol = POM
TRADE NAME = Delrin Celcon
Chemical Name = Polyoxymethylene (Delrin)
Specific Weight kg/dm3 = 1.42 ASTM D.792
Water Absorbtion N% = 0.9 ASTM D.570
Tensile Strength Kg/cm2 = 680 ASTM D.638
Stretch % = 75 ASTM D.638 ASTM
Modulus of Tensile Elasticity kg /cm3 = 29.000 ASTM D.638
Impact Strenght IZOD Kg.cm/cm = 18 at 25 deg C and 10 at 40 Deg C ASTM D.256
Rockwell Hardness = 120 Scale R ASTM D.785
Max Operation Temp = 150 deg C
ASTM = This is the test method used.
Other information = These balls will not float

Delrin Balls: Delrin is the name commonly used for the less commonly known polyoxymethylene (POM) acetal plastic. It has high mechanical strength and rigidity, is tough and tolerant to repeated impacts and has a good long term fatigue endurance. It has excellent resistance to petroleum based solvents, moisture and other neutral chemicals. Its has good electrical insulating properties and self lubricates in use. It can be operated within a wide operating temperature range up to 150 Deg C.
Note: There are many factors which may influence the performance of this product, temperature, chemical exposure etc. - always test for your own application before selecting large quantities of this product.
Benefits: Self lubricating, tough, durable

not really what you asked for though sorry

yes a simple jig as you describe nebbian would be great once i have some cad skills i will draw one, i do have a couple that are very slightly out of line but ive marked them to the effector and watched if they turn when in use and they dont so its holding its calibration well i was worried that they would turn and change the effector angle noticeably , i would like a jig to redo them though, my semiU 3dr kit came with m3 threaded bar and metal ball joints, the problem with them was the amount of movement was limited they restricted the build space to much , and these new ones will go down and be parallel to the towers giving me much more build space.

i had real problems trying to drill stainless ones even the so called low carbon soft ones were not soft,

thanks for your replys guy

forest

Quote
forest
hi guys thanks for your comments

Quote
etfrench
It sounds like a good alternative to magnets for heated enclosures.

Do you have the specifications for the spherical tolerances?

there is this tech data for them

ISO Symbol = POM
TRADE NAME = Delrin Celcon
Chemical Name = Polyoxymethylene (Delrin)
Specific Weight kg/dm3 = 1.42 ASTM D.792
Water Absorbtion N% = 0.9 ASTM D.570
Tensile Strength Kg/cm2 = 680 ASTM D.638
Stretch % = 75 ASTM D.638 ASTM
Modulus of Tensile Elasticity kg /cm3 = 29.000 ASTM D.638
Impact Strenght IZOD Kg.cm/cm = 18 at 25 deg C and 10 at 40 Deg C ASTM D.256
Rockwell Hardness = 120 Scale R ASTM D.785
Max Operation Temp = 150 deg C
ASTM = This is the test method used.
Other information = These balls will not float

Delrin Balls: Delrin is the name commonly used for the less commonly known polyoxymethylene (POM) acetal plastic. It has high mechanical strength and rigidity, is tough and tolerant to repeated impacts and has a good long term fatigue endurance. It has excellent resistance to petroleum based solvents, moisture and other neutral chemicals. Its has good electrical insulating properties and self lubricates in use. It can be operated within a wide operating temperature range up to 150 Deg C.
Note: There are many factors which may influence the performance of this product, temperature, chemical exposure etc. - always test for your own application before selecting large quantities of this product.
Benefits: Self lubricating, tough, durable

not really what you asked for though sorry

yes a simple jig as you describe nebbian would be great once i have some cad skills i will draw one, i do have a couple that are very slightly out of line but ive marked them to the effector and watched if they turn when in use and they dont so its holding its calibration well i was worried that they would turn and change the effector angle noticeably , i would like a jig to redo them though, my semiU 3dr kit came with m3 threaded bar and metal ball joints, the problem with them was the amount of movement was limited they restricted the build space to much , and these new ones will go down and be parallel to the towers giving me much more build space.

i had real problems trying to drill stainless ones even the so called low carbon soft ones were not soft,

thanks for your replys guy

forest

Shame they want 9mm balls 100 mm ones with a ready drilled and tapped with M4 holes are readily available on Ebay for less that 20p each (Around £8 for a bag of 50) or £2.50 for 16 see 10mm Dia balls with M4 hole

maybe you could get the designer of the Effector and carriages to do some for 10mm balls then you can Glue a M4 grub screw into the balls and then into Carbon Tube

Drilling jig can be made much simpler:
Take a piece of stock several times wider than the ball (It can be aluminum or mdf or delrin or any material that is easy to drill) and 20mm to 30mm thick.
Drill one hole the size of the bolt or arm.
Turn the piece over and drill another hole smaller than the diameter of the ball and deep enough for the ball to touch the outer diameter of the hole.

I like the idea of delrin balls for a delta 3D printer and the string to keep the effector in place reminds me of this youtube video that explains it very well. I think that guy ultimately gave up spectra because of some resonance or something along this.

Making a drilling jig for the delrin balls shouoldn't be very difficult, a cube with a spherical cutout on the inside, cut in half with two screw holes to clamp the sphere and a hole where you would insert a bushing to guide the drillbit should be fairly easy to 3D print/put together.
Another jig to keep the diagonal rods the same length is already the norm so that is not something new here.

Could you have a video uploaded with the running printer?

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