cdsl-cad/backend/agent/skills/cad-engine/references/part-skills/source/planning/mounting-plate.planning.md

Mounting Plate Planning Skill

When to use

• The request describes a flat mounting plate, base plate, adapter plate, panel, fixture plate, or spacer plate.
• The dominant body is a prismatic plate with functional holes, slots, counterbores, countersinks, threaded holes, pockets, or a central clearance cutout.
• The plate locates, fastens, spaces, or supports other components from planar datum faces.

Do not use when

• The primary geometry is an axisymmetric flange with a circular bolt pitch pattern.
• The plate is only a secondary base under a bearing housing, bracket, motor body, or cylindrical module.
• The part is a true 3D bracket with vertical webs, lugs, arms, or side walls that control the design.
• The request is for sheet-metal bends, formed panels, or decorative flat art rather than a machined plate.

Recognition features

• Rectangular, square, rounded-rectangle, or simple profile plate with mostly uniform thickness.
• Holes are located from datum edges, centerlines, or symmetric offsets instead of arbitrary visual placement.
• Common hole types include clearance holes, threaded holes, counterbored holes, countersunk holes, dowel holes, and through holes.
• Cutouts can be central circular holes, rectangular windows, slots, pockets, or weight-reduction openings.
• Edge chamfers and small fillets are usually finishing operations, not the defining shape.

Core invariants

• Establish the base plate envelope, thickness, top face, bottom face, and edge datum references before adding holes.
• Keep mounting holes fully constrained by edge margins, centerlines, pitch, symmetry, or functional datums.
• Model holes as real cuts or standard hole features; do not leave sketch circles on the face.
• Use one seed hole or hole group plus pattern/mirror when the layout is regular.
• Choose hole type from function: clearance for bolts, threaded/tapped for fastening into the plate, counterbore/countersink for flush screw heads, slot for adjustment.
• Apply chamfers and fillets after functional holes and cutouts so edge treatment does not distort hole geometry.

Parameter roles

• length, width, and thickness define the blank.
• corner_radius or corner_chamfer controls perimeter treatment when requested.
• edge_margin_x, edge_margin_y, pitch_x, and pitch_y locate rectangular hole groups.
• central_cutout_width, central_cutout_length, or central_bore_diameter define clearance openings.
• hole_diameter, thread_size, counterbore_diameter, counterbore_depth, countersink_angle, and slot_length define fastener features.

Construction sequence

1. Create a constrained base sketch for the plate outline and extrude it to thickness.
2. Define datum centerlines, edge offsets, and symmetry references on the main face.
3. Add the central clearance hole, rectangular cutout, or pocket if it controls component clearance.
4. Add the first functional hole using the correct hole type and end condition.
5. Replicate regular hole groups with linear pattern, circular pattern, or mirror according to layout intent.
6. Add slots, secondary pockets, bosses, or local relief cuts only after primary mounting references are stable.
7. Finish with perimeter chamfers, small fillets, and deburring details.

Common failures

• Treating every round mark as the same generic hole and losing counterbore/thread/countersink meaning.
• Placing holes by eyeballing coordinates instead of datum margins and symmetry.
• Using a flange bolt-circle pattern for a rectangular plate grid.
• Adding chamfers before holes, causing holes or counterbores to be clipped.
• Over-modeling decorative bevels while missing the functional fastening layout.
• Combining unrelated bracket walls or cylindrical housings into the mounting plate body.

Evidence summary

• Current library evidence: 207 previously reviewed SCAD58 mounting/base plate descriptions.
• Latest run evidence: repeated accepted insights for mounting_plate_with_holes, plan_mounting_plate_with_holes, extrude_rectangular_plate, base_plate_with_mounting_holes, central cutouts, threaded holes, counterbored holes, linear patterns, and edge chamfers.
• Frequent operations in the latest run: Extrusion, HoleWzd, Cut, LinearPattern, MirrorPattern, Chamfer, Fillet.
• Source: CAD-SkillX offline review of SCAD58 descriptions, STEP summaries, and SolidWorks feature evidence.

Retrieval metadata

Triggers:

• mounting plate
• base plate
• adapter plate
• fixture plate
• flat plate with holes

Secondary triggers:

• hole grid
• edge margins
• counterbored holes
• threaded holes
• central cutout
• slots

Operation triggers:

• extrude base plate
• hole wizard
• linear pattern
• mirror holes
• cut central opening
• chamfer edges last

Exclusions:

• flange bolt circle
• bearing housing
• shaft
• 3d bracket
• sheet metal bend