Standard mates (coincident, concentric, distance) in Solidworks - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding the Coincident Mate

In SolidWorks, what is the primary effect of applying a coincident mate between two planar faces?

A It aligns the two faces so they share the same plane and touch each other.

B It makes the two faces rotate concentrically around a common axis.

C It sets a fixed distance between the two faces without touching.

D It locks the two faces so they cannot move in any direction.

💡 Hint

Think about what happens when you press two flat surfaces together.

A coincident mate forces two faces or edges to lie on the same plane and touch, like pressing two sheets of paper flat together.

🧠 Conceptual

intermediate

Purpose of a Concentric Mate

Which scenario best describes when you would use a concentric mate in SolidWorks?

A To fix two faces so they cannot move relative to each other.

B To align two holes so their centers share the same axis.

C To set a specific distance between two edges.

D To make two faces parallel but not touching.

💡 Hint

Think about how a bolt fits inside a hole.

A concentric mate aligns the centers of two cylindrical or circular features so they share the same axis, like a bolt inside a hole.

🧠 Conceptual

advanced

Calculating Distance Mate Value

You have applied a distance mate between two faces in SolidWorks. If the distance is set to 50 mm, what will be the measured gap between these faces in the assembly?

A It depends on the face sizes

B 0 mm

C 100 mm

D 50 mm

💡 Hint

Distance mate sets a fixed gap between faces.

A distance mate fixes the gap between two faces to the specified value, so the gap will be exactly 50 mm.

🔧 Formula Fix

advanced

Troubleshooting a Concentric Mate Failure

You tried to apply a concentric mate between a cylindrical pin and a hole, but SolidWorks shows an error and does not allow it. Which of the following is the most likely cause?

A The pin and hole have different axis directions or are not cylindrical.

B The pin is larger than the hole.

C The distance mate is applied instead of concentric mate.

D The pin and hole are already coincident.

💡 Hint

Concentric mates require matching cylindrical axes.

A concentric mate requires both features to have cylindrical geometry and aligned axes. If axes differ or geometry is not cylindrical, the mate fails.

🎯 Scenario

expert

Combining Mates for Complex Assembly

You are assembling a shaft into a bearing housing. You want the shaft to rotate freely inside the bearing but not move axially. Which combination of mates should you apply?

A Apply a coincident mate on the shaft end and a concentric mate on the shaft body.

B Apply two coincident mates on opposite faces of the shaft.

C Apply a concentric mate to align axes and a distance mate to fix axial position.

D Apply only a distance mate to fix the shaft in place.

💡 Hint

Think about how to allow rotation but prevent sliding.

A concentric mate aligns the shaft and bearing axes allowing rotation, while a distance mate fixes the axial position preventing sliding.

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