HP 97 Printer Gear

[RPZ]

Finally. I have successfully 3d printed an HP 97 printer idler gear.

Parameters were found on this wonderful forum, plus some measurements, and some guesswork.

80 pitch
30 teeth
0.180" total width
20 degree pressure angle
3/32" bore

The hub was not used as it is unnecessary and I thought it would be easier to see wear. Also either side of the gear can be used if there are imperfections.

The drawing was created with OpenSCAD version 2015.03-2 and modified public domain gear code.

Gcode for printer was created using Cura version 15.04.6.

Printing was done using a Monoprice Select Mini 3D Printer V2 ($219) and Hatchbox PLA.

Cost is about 2 cents per gear and some time.

I am not cheap, I am thrifty.


To test I ran a short counting loop with a print space and a pause.

Gears were not cleaned or lubricated.

After 24 hours and 43,000 cycles I could not see any wear or any change in sound.

I lubricated the gears with some silicone grease and saw no change. This may not be a good idea as I don't know how the grease may react with pla or HP plastic over time. Might also collect dust and dirt and cause a problem.


I uploaded the stl file to Shapeway.com and got immediate online quotes.

One gear printed with versatile plastic is $5.00 plus a fixed cost of $10.15 for a total of $15.15. 2 gears would be $20.15.

They can print with all kinds of interesting materials.


Versatile plastic is $5.15 + $10.15 for a total for one gear of $15.15.

Fine detail plastic is $7.50 + $10.46 for a total for one gear of $17.96.

Steel is $15.00 + $11.38 for a total for one gear of $26.38.


Now it gets interesting. A gear 20 times as wide is not much more and could be sliced up.


20 x wide gear (3.6")

Versatile plastic is $5.51 + $10.21 divided by 20 is $0.79 per gear.

Fine detail plastic is $9.93 + $10.77 divided by 20 is $1.04 per gear.

Steel is $38.17 + $14.25 divided by 20 is $2.62 per gear.


I don't need that many gears especially since mine seem to work but may order some to check out these other materials and to see what accuracy can be done with a really good printer.


Regards, Rick





---eof