Guides

Your first part: a gear

About ten minutes, and no CAD experience needed.

1. Start OpenPara and press Part Generator on the ribbon.
2. Choose Spur gear. Leave Module at 2 and Number of teeth at 20.
3. Look at the 3D preview. The numbers on the right (pitch diameter, outside diameter and so on) update as you type.
4. Change the face width and the bore diameter to what you need.
5. Press OK. The gear is added as one feature. Double-click it in the tree any time to change the numbers.
6. Save with File > Save.

A gear train from centre distances

1. In the Part Generator, open the Gear systems tab and choose Gear train.
2. Define gear 1: module, teeth, pressure angle, width and bore. Use a helix angle above 0 for helical gears; the hands alternate for you.
3. For gear 2, choose Centre distance and type the distance you have room for. OpenPara picks the nearest whole tooth count and uses profile shift to make up the small remainder.
4. For a third gear, choose another distance, a ratio, or the total of both distances. You can bend the chain at the middle gear.
5. Read the results: centre distances, ratios, and each gear's position and turn angle.
6. Press Open the parts. Each gear opens as its own part, unsaved. Put them together in an assembly using the positions and turn angles shown.

A planetary set

1. In Gear systems, choose Planetary set.
2. Choose which two gears set the size, for example sun and planet teeth. The ring always has sun + 2 × planet teeth.
3. Choose the number of planets. They must be equally spaced, so the sun plus ring teeth must divide evenly. If your choice does not work, OpenPara lists the counts that do.
4. Read the ratios for holding the ring, the sun or the carrier still.
5. Press Open the parts: three parts open (sun, planet, ring). Make the assembly yourself, adding as many planets as you chose, using the angles and radius shown. There is no carrier part.