http://blogs.solidworks.com/solidworksblog/2015/10/mbd-implementation-10-dos-and-10-donts-dont-hesitate-part-1.html

Assess PMI Consumption

Identify Data Needs

Create MBE Vision Plan

• 3 DimXperts

• 2D Drawings – Introduced with version 2007

• 3D Parts – Introduced with version 2008

• 3D Assemblies – Introduced with version 2016*

*SOLIDWORKS MBD license required

•Machined Parts • Milled • Drilled • Turned

•Geometric and Plus-Minus Tolerance

• Sheetmetal • Bends not supported --- Use Reference Dimension

• Prismatic type features are supported (planes, holes, slots)

• Molded/Casted Parts • Draft not supported

• Profile tolerancing is supported

• Use reference geometry (planes and intersections)

• Special Geometries • Including gears, threads and cams

Countersink Cone Hole Counterbore

Slot Notch Boss Cylinder

Pocket Surface Chamfer Fillet

Plane

Width

Intersect Line Intersect Point Intersect Plane

Plane intersection between a cylinder

and a cone

Line intersection between a two

planes

Point intersection between a cylinder

and a plane

DimXpert_Models/SAR1.SLDPRTDimXpert_Models/SAR2.SLDPRT

• Model faces colored based on status • Green = Fully Constrained

• Yellow = Under Constrained

• Red = Over Constrained

• Native Color = Not Recognized by DimXpert

• Sketch Dimensions • Facilitate part creation, configurations, design tables

• Linked to construction geometry not present in finished part

• Aren’t always consistent with methods used for manufacturing

• Don’t always meet requirements necessary to support geometric tolerancing

• DimXpert Dimensions • Communicate part’s functional requirements

for assembly, manufacturing and inspection

• Always associated with manufacturing features

• Always associated with a tolerance

• Dimensions (basic) associated with geometric tolerances originate from and are oriented to the datum reference frame

Tolerance type and values created by Size Dimension and Auto Dimension Scheme

Chain Baseline

1. ADS (Automatic Dimensioning Scheme) and Geometric Tolerancing

2. ADS and Plus-Minus Tolerancing

3. ADS and Selected Features

4. ADS and the Wedge

5. ADS and Concentric Features

6. Feature Selector

7. Manual Tolerancing

8. More Feature Selector

DimXpert_Models/DX Demo1.SLDPRT

DimXpert_Models/DX Demo2.SLDPRT

DimXpert_Models/DX Demo3.SLDPRT

DimXpert_Models/DX Demo4.SLDPRT

Plus and Minus

Geometric

DimXpert_Models/DX Demo5.SLDPRT

DimXpert_Models/DX Demo6.SLDPRT

Location Dimension Size Dimension

DimXpert_Models/DX Demo7.SLDPRT

DimXpert_Models/DX Demo8.SLDPRT

Intersect Line Intersect Point Intersect Plane

Plane intersection between a cylinder

and a cone

Line intersection between a two

planes

Point intersection between a cylinder

and a plane

DimXpert_Models/SAR1.SLDPRTDimXpert_Models/SAR2.SLDPRT

• Notes

• BOM

• Title Blocks

• DimXpert and Reference Dimension Support in 2D Drawings

• Tolerance stack-up analysis is the study of dimension and tolerance schemes to determine potential form, fit, and function problems in parts and assemblies

• Included with SOLIDWORKS Professional and Premium

What the permissible gap (G) between Part1 and Part4 ?

• Assumes dimensions vary within the entire range of their tolerance zones and that the accumulation of tolerances will experience all possible variations

Gmin = L1 + L2 + L3 + L4… + Ln = L1 + L2 + L3 + L4

= 152.75 + (-60.75) + (-42) + (-50.5)

= -0.5 Interference

• Assumes dimensions vary randomly within a normal distribution (±3σ) centered about midpoint of the tolerance zone.

G = Gnominal ± √ T12 + T22 + T32… TN2

= 2 ± √ 0.252 + 0.752 + 12 + 0.52 = 2 ± 1.369

Gmin = 0.631, Gmax = 3.369

Gnominal = 153 - 60 - 41 - 50

= 2

• It is incorrect to think max worst case is when the parts are at their largest and min worst case is when they are at their smallest

Part Nominal Assembly Worst-case

Maximum Worst-case

Minimum

Functional Requirement: D >= 39

Top Plate Angle Bracket Bushing

Before After

To reduce the tolerance stack by 0.8

(39 – 38.2) the tolerance of each

dimension would have to be changed

to ± 0.1

Before After

By increasing the width between the faces

locating the two angle brackets by 1 mm the

results for the minimum worst-case gap would

be 39.2 (38.2 + 1)

By adding a dimension between the planes which locate

the axel supports and removing the 40 dimension on the

right side of the part the tolerance stack between the

planes is reduced from ± 1.1 to ± 0.3. As a result the new worst-case minimum dimension would be 39.

Before

After Before

http://blogs.solidworks.com/solidworksblog/2015/10/mbd-implementation-10-dos-and-10-donts-dont-hesitate-part-1.html

Assess PMI Consumption

Identify Data Needs

Create MBE Vision Plan