Why Standard mates (coincident, concentric, distance) in Solidworks? - Purpose & Use Cases

The Big Idea

What if you could snap parts together perfectly every time without endless adjustments?

The Scenario

Imagine trying to assemble a complex machine by manually measuring and aligning each part with a ruler and protractor. You have to guess if two holes line up perfectly or if two cylinders share the same center. It's like trying to fit puzzle pieces without the picture on the box.

The Problem

This manual approach is slow and full of mistakes. Small misalignments cause parts not to fit, leading to wasted time and frustration. Repeated adjustments and re-measurements make the process painful and error-prone.

The Solution

Standard mates like coincident, concentric, and distance in SolidWorks automate alignment. They let you snap parts together exactly where they should be, ensuring perfect fit without guesswork. This saves time and reduces errors dramatically.

Before vs After

✗ Before

Measure distance, adjust part, re-measure, repeat

✓ After

Apply 'coincident mate' to align faces, 'concentric mate' for holes, 'distance mate' to set spacing

What It Enables

With standard mates, you can build precise assemblies quickly and confidently, focusing on design instead of tedious alignment.

Real Life Example

When designing a bicycle, using concentric mates ensures the wheel hub perfectly aligns with the frame's axle hole, so the wheel spins smoothly without wobble.

Key Takeaways

Manual alignment is slow and error-prone.

Standard mates automate precise part positioning.

This leads to faster, more accurate assembly design.

Practice

1. Which type of standard mate in SolidWorks makes two faces or edges touch exactly?

easy

A. Coincident mate

B. Concentric mate

C. Distance mate

D. Parallel mate

Solution

1. Step 1: Understand the Coincident Mate

   A coincident mate forces two faces or edges to touch exactly, aligning them perfectly.

2. Step 2: Compare with Other Mates

   Concentric mates align circular parts along the same axis, and distance mates keep parts a fixed space apart, so they do not make faces touch.

3. Final Answer:

   Coincident mate -> Option A

4. Quick Check:

   Faces touching = Coincident mate [OK]

Hint: Faces or edges touching? Choose coincident mate [OK]

Common Mistakes:

• Confusing concentric with coincident
• Thinking distance mate makes parts touch
• Mixing parallel mate with coincident

2. Which of the following is the correct syntax to apply a concentric mate between two circular edges in SolidWorks?

easy

A. Mate.AlignCenters(edge1, edge2)

B. Mate.Add(edge1, edge2, 'distance')

C. Mate.SelectFaces(face1, face2).ApplyCoincident()

D. Mate.SelectEdges(edge1, edge2).ApplyConcentric()

Solution

1. Step 1: Identify the correct method for concentric mates

   The method to apply a concentric mate involves selecting edges and applying the concentric constraint, matching Mate.SelectEdges(edge1, edge2).ApplyConcentric().

2. Step 2: Eliminate incorrect options

   Mate.Add(edge1, edge2, 'distance') applies a distance mate, Mate.SelectFaces(face1, face2).ApplyCoincident() applies coincident on faces, and Mate.AlignCenters(edge1, edge2) is not a valid SolidWorks syntax.

3. Final Answer:

   Mate.SelectEdges(edge1, edge2).ApplyConcentric() -> Option D

4. Quick Check:

   Concentric mate syntax = Mate.SelectEdges(edge1, edge2).ApplyConcentric() [OK]

Hint: Select edges then apply concentric mate method [OK]

Common Mistakes:

• Using face selection for concentric mate
• Confusing distance mate syntax with concentric
• Using non-existent methods like AlignCenters

3. Given two cylindrical parts with axes aligned, what is the result of applying a concentric mate between their circular edges?

medium

A. The parts are fixed at a set distance apart.

B. The parts' axes align and their circular edges share the same center axis.

C. The parts' flat faces touch exactly.

D. The parts rotate freely without alignment.

Solution

1. Step 1: Understand the effect of a concentric mate

   A concentric mate aligns the axes of circular edges so they share the same center line.

2. Step 2: Compare with other mate effects

   Distance mates keep parts apart, coincident mates make faces touch, and free rotation means no mate applied.

3. Final Answer:

   The parts' axes align and their circular edges share the same center axis. -> Option B

4. Quick Check:

   Concentric mate aligns axes = The parts' axes align and their circular edges share the same center axis. [OK]

Hint: Concentric mate aligns circular axes, not faces [OK]

Common Mistakes:

• Thinking concentric sets distance
• Confusing coincident with concentric
• Assuming free rotation after mate

4. You tried to apply a distance mate between two parts but the parts snap together instead of staying apart. What is the likely cause?

medium

A. The distance value was set to zero.

B. You applied a coincident mate instead of a distance mate.

C. The parts are fixed and cannot move.

D. You applied a concentric mate by mistake.

Solution

1. Step 1: Check the distance mate value

   If the distance is zero, parts will snap together, appearing coincident.

2. Step 2: Rule out other causes

   Applying coincident or concentric mates causes different behaviors; fixed parts do not move but distance mate with zero causes snapping.

3. Final Answer:

   The distance value was set to zero. -> Option A

4. Quick Check:

   Distance zero snaps parts together = The distance value was set to zero. [OK]

Hint: Check distance value; zero means no gap [OK]

Common Mistakes:

• Confusing coincident with distance mate effect
• Ignoring zero distance input
• Assuming concentric mate affects distance

5. You need to assemble a shaft inside a hole so that the shaft's axis aligns with the hole's axis and the shaft is exactly 5 mm away from the hole's bottom face. Which mates should you apply?

hard

A. Apply a distance mate of 5 mm between shaft and hole edges only.

B. Apply two coincident mates: one for axes and one for bottom faces.

C. Apply a concentric mate between shaft and hole edges, then a distance mate of 5 mm between shaft bottom face and hole bottom face.

D. Apply a concentric mate and a coincident mate between bottom faces.

Solution

1. Step 1: Align shaft and hole axes

   Use a concentric mate between the circular edges of shaft and hole to align their axes.

2. Step 2: Set the gap distance

   Apply a distance mate of 5 mm between the shaft's bottom face and the hole's bottom face to maintain the required space.

3. Final Answer:

   Apply a concentric mate between shaft and hole edges, then a distance mate of 5 mm between shaft bottom face and hole bottom face. -> Option C

4. Quick Check:

   Concentric for axis + distance for gap = Apply a concentric mate between shaft and hole edges, then a distance mate of 5 mm between shaft bottom face and hole bottom face. [OK]

Hint: Use concentric for alignment, distance for spacing [OK]

Common Mistakes:

• Using coincident mate for axis alignment
• Applying distance mate between edges only
• Mixing coincident and concentric incorrectly