### Parameters Tab

Use the Parameters tab to define the geometry parameters for the gear. Refer to the gear's blueprint to define the parameters.

Define Gear dialog box – Parameters tab for cylinder gear

Gear Parameters Area

Number of teeth: This box specifies the number of teeth around the gear.

Note: If you change the number of teeth, update the Teeth List to be measured list and box on the Profile, Helix/Lead, and Tip/Root Circle tabs if applicable.

Normal module or Diametral pitch: Consult the appropriate gear standard for the definition of this parameter. The expected parameter for an English (INCH) gear is Diametral pitch. The expected parameter for a metric (MM) gear is Normal module. The parameter depends on the unit of measurement you select in the Units area.

Normal pressure angle: Consult the appropriate gear standard for the definition of this parameter.

Face width [b]: This box specifies the width along the face of the gear tooth. It is always a positive number. See A in the diagram below:

A - Face Width
B - Tooth Height

Addendum modification coefficient [x]: Consult the appropriate gear standard for the definition of this parameter.

Gear Area

These options specify whether the gear is External (teeth on the outside) or Internal (teeth on the inside).

Units Area

The INCH and MM options define the units of measurement to use in the created part program and for any typed distance values in PC-DMIS Gear.

Flank Direction Area

These options define the flank direction of the gear:

- Straight: Spur gear

- Left: Left-handed helical gear

- Right: Right-handed helical gear

Helix Angle Area

These options define the angle of the helix of the gear.

Complete Gear Area

Specifies whether the gear is a complete gear:

- Yes: T he gear is complete and has all teeth available for measurement.

- No: T he gear is incomplete (or segmented). For a segmented gear, the Incomplete gear definition area becomes available.

Incomplete Gear Definition Area

This area is available for a segmented gear only. In the Tooth No. box, type the ranges of the tooth segments available on your segmented gear.

You can use the browse button to display the Edit dialog box and define the segments of the gear.

Note: The Number of teeth represents all the teeth that would be present around the gear if there were no gaps in the tooth pattern. The purpose of defining segmented gears is to remove the gaps from consideration for measurement. The incomplete gear shown below would be defined as having 36 teeth rather than the 18 teeth (six teeth in three actual segments) that actually exist.

Example of a Segmented Gear

Example of a Segmented Gear

For example, to define the above segmented gear, the value for the Number of teeth option should be 36. Click on the browse button to display the Edit dialog box and define the tooth numbers available on the segmented gear. In this example, you would define three segments with the respective tooth numbers available for measurement:

The Edit (segment) dialog box shows a range of three segments of six teeth each, making a total of 18 teeth. Notice that the teeth segments ranging from 7-12, 19-24, and 31-36 were cleared from the list to reflect the three incomplete or missing segments.

Click Add to add the segments. To delete an existing segment, highlight the data that needs to be removed, and select Clear.

When you click OK, the teeth segments appear in the Tooth No. box:

There are two ways to generate the segment list:

- Using “Auto Range”: When you select this option in the Edit dialog box, all of the teeth segments will be calculated according to the Number of teeth, Start Tooth No., End Tooth No., and Segments Number. For example, for a gear with 26 teeth:

- 1. Select Auto Range to automatically define gear segments.

  2. Type 4 for the Segments Number value, which means the teeth will be divided equally into 4 parts.

  3. Type 1 for the Start Tooth No. value, and type 4 for the End Tooth No. value. This will measure tooth #1, #2, #3, #4 in every section (since we are working with 26 teeth divided by 4 segments, there should be 6 teeth in every section). Tooth #5 and #6 are not measured.

  4. Click Add to populate the segment list. You will see the result is “1-4”, “7-10”, “13-16”, and “19-22”. This defines the teeth to be measured. You may need to experiment with this method to get the desired result.

  5. To save the segment list, select OK. To close the dialog box without saving your changes, select Cancel.

- Manually adding segment ranges: When Auto Range is unchecked, you can add segments manually. Segments Number is disabled in this case, and you need to specify Start Tooth No. and End Tooth No., and then click Add to add the defined segment to the list. Continue this process until each segment is defined. For example, you could do the following for a gear with 26 teeth:

1. Deselect Auto Range to manually define gear segments.

2. Type 1 for the Start Tooth No. value, and 4 for the End Tooth No. value.

3. Click Add to add segment “1-4” to the list.

4. Repeat steps 1 and 2 for the ranges "7-10", "13-16", and "19-22". This completes that same list that was created in the auto range example.

5. To save the segment list, select OK. To close the dialog box without saving your changes, select Cancel.

Quality Standard and Grade Area

Gears are manufactured and measured with reference to various international standards. In this area, select the standard and enter the G rade specified for your gear on the blueprint. The standards supported by PC-DMIS are available for selection; for example, AGMA 2000-A88.