×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

accurate involute gear tooth profile to model for SLA

accurate involute gear tooth profile to model for SLA

accurate involute gear tooth profile to model for SLA

(OP)
I am working on four gears and trying to create 3D models for SLA and also for mold.  I looked at several websites and Pro/E tips but none of them are giving accurate profiles. I appreciate anybody who can help me in creating a 3D model.

My gear parameters are:

1. PD = 1.7003
   No. of teeth = 81
   pressure angle =20
2. PD = 1.8892
   No.of teeth = 90
   pressure angle =20
3. PD =2.0691
   No. of teeth = 91
   Pressure angle =20
4. PD = 1.7947
   No. of teeth = 79
   Pressure angle =20

Again any help is appreciated

Thanks and regards,

Ramesh

RE: accurate involute gear tooth profile to model for SLA

Can you explain the PD? Is it the Diametral Pitch (Module) or the Pitch Diameter?

RE: accurate involute gear tooth profile to model for SLA

(OP)
Sorry, PD is Pitch Diameter.  Thickness of the gear is .156"  in all cases

RE: accurate involute gear tooth profile to model for SLA

Something doesn't add up. What is the diametral pitch of the gears. When I calculate it I do not receive whole numbers, how did you came to those pitch diamters?

It seems that the gears are diametral pitch 48 and 44, if so what is the gear accuracy and how did you recieve the pitch diameters?

RE: accurate involute gear tooth profile to model for SLA

(OP)
Yes, diametral pitches are not round numbers.  I had use the pitch diameters since center distances and gear ratioes are controlled by other geometry which I cannot change.  Since, I am planning to use molding to make plastic gears, I am thinking that it is OK to have these kind of diametral pitch numbers.

Gear accuracy AGMA 6.

RE: accurate involute gear tooth profile to model for SLA

OK. If you want to get an accurate gear drawing you should get the free software GEARGN.ZIP which you can find in http://www.mfgworld.com/fileid.html . This is a DOS based program that export DXF files. I assume that you can import the DXF file to PRO/E and create a solid from it.

I have done this with Solidworks but since the DXF file is basically a bunch of large number of points the program had diffuclties to handle it and the process took a very long time and always succesfully. I hope PRO/E will do better.

If you intend to create molds then this program can create the G-CODE for wire EDM.

RE: accurate involute gear tooth profile to model for SLA

konduri,
If you want "accurate" models, then you need to know more about the gears:
Major Dia
Root Dia
Tooth thickness (at known diameter, usually PD)
These data do not have to be standard (addendum does not have to be 1/DP etc.)
and also how the root fillet looks like.
The tooth profile and fillet root curve can be calculated using the data mentioned above, for a perfect involute.
Not a simple calculation, but it can be done.
Not that long ago there was a Lisp program (created by Diamonjim) published in this forum; if you have access to AutoCad, you can run it, save the 2D profile as a dxf and then you can import it to any CAD and extrude it to create the 3D model.
But think twice before you give the 3D model to somebody as a math model for machining actual gear. I personally would not do it - unless the gears quality is not very important.

RE: accurate involute gear tooth profile to model for SLA

I would use the .5 module gearing
and go with expanded center distance.
48 diametral pitch could also be used
and go with shortened center distance.
I think I posed answeres to this on
another forum as well or to your
e-mail to me.  If you need the details
let me know.

RE: accurate involute gear tooth profile to model for SLA

(OP)
Steve,

Gear 1 and Gear 2 mesh with each other.  Center distance for these two gears is 1.79473

Gear 3 meshes with itself - center distance is 2.06912

Gear 4 meshes with itself - center distance is 1.79473

I downloaded your GEAR CAM program but it requires password to use it.  

Thanks.

Ramesh

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources