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This is a small tutorial detailing step-by-step instructions to model a plastic hairbrush in SolidWorks. The

model was made in SolidWorks 2010, but, since there’s no new functionality involved in the process, the

instructions can still be useful even for those working with previous versions.

1. Open a new part document in SolidWorks and set the units to inches.

2. Open a sketch on the Front plane. Sketch an ellipse, centered at the origin. I used the following

measurements, which I obtained from one of my own hairbrushes. You can use the same

measurements, for convenience.

3. Extrude Sketch1 4.3 inches from the sketch plane, as seen in the image below.

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4. On the Feature toolbar, look for Reference Geometry and select Plane to create a new reference

plane using the Front plane as reference. Set the new plane a distance of 4.8 inches from the

Front plane as shown in the image.

5. Open a new sketch on the Top plane and sketch a three point arc on one of the ends of the

elliptical extrusion we made earlier, just like you see in this image. Notice that end points of the

arc are coincident with the silhouette edges of the extrusion.

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6. Use the sketch from step 5 to make a cut at the end of the extrusion, using Extruded Cut from

the features toolbar. Cut through all in both directions. Repeat the same procedure for the

other end of the extrusion.

7. On Plane 1, created on step 4, open a new sketch and draw a 0.9 in diameter circle centered at

the origin.

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8. Create a loft between the circle sketch and the edge of the extrusion (Features, Loft). Just like in

the image below, under Start/End Constraints use Normal to Profile for the sketch (Start

Constraint in this case) and None for the edge (End Constraint). Use a tangent length of 1 for the

sketch’s Normal to Profile constraint.

9. Use the Shell feature with a thickness of 0.18 in and removing only the face shown in blue in the

image.

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10. Open a new sketch on the Top plane and draw a zigzag line like the one shown in the following

image. Tip: draw half of the zigzag line first and mirror with respect to the vertical construction

line, then finish adding dimensions.

11. Using Offset Entities, create a slot out of the zigzag line from the previous step. Use the

parameters you see in the following image. Offset distance of 0.05 in, bi-directional, cap the

ends with arcs and make the base construction.

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12. Use the sketch of the slot created in the previous step to extrude a cut through all in both

directions (use Extruded Cut from the Features toolbar).

13. After extruding the cut, and if you so wish, add a 0.04 in fillet to the 12 edges shown in the

image.

14. Add a 0.01 in fillet to the edge shown in the image. Use tangent propagation. Add another

similar fillet to the edge on the opposite side.

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15. If it isn’t showing already, show the Sketch5, the sketch of the zigzag slot. To show the sketch,

right click on it in the Feature Manager and select Show from the fly out toolbar. You’ll need

that sketch for the following step.

16. On the Features toolbar, click on Linear Pattern. Under Direction 1, select the vertical

construction line in Sketch 5. Enter a distance of 0.43 in as the space between instances in the

pattern and 9 for the number of instances. Under features to pattern, select the cut extrude and

the fillets created in steps 12 through 14 (they are highlighted in blue in the fly out feature

manager. Check that the direction of the pattern is like that of the image and reverse it if

necessary.

17. Open a new sketch on the Top plane. Use Offset Entities (Sketch toolbar) to offset the

construction zigzag line in Sketch 5 a distance of 0.2 in, as you see in the image. Reverse the

direction if necessary.

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18. Use Insert, Curve, Projected to project the sketch from the previous step on the surface of the

body, just below the slot, as you see in the image. For projection type select sketch on faces. The

sketch, of course is Sketch6 (shown in a blue) and the face is the face of the body, shown in pink.

The projection is shown in yellow.

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19. Now that you have the curve projected on the face of the body, you are going to create a couple

of reference points on the zigzag line. Later, you’ll use these points as an aid to create reference

planes and, ultimately, extrude the holes for the bristles. Go to Reference Geometry, Point and

create reference points in the middle of the two segments, as shown in the following image. In

the image, Point 1 has already been created and we’re in the process of adding Point 2 the same

way Point 1 was added: hover with your mouse over the line segment until you see a point show

up in the middle and then click on it; that’s your first reference. Now click on the face of the

body for a second reference. This creates a point that is in the middle of the line segment, on

the face of the brush.

20. Now we’re going to create five different reference planes that will be used as an aid in extruding

holes for the bristles. Go to Reference Geometry, Plane and choose the point at the left end of

the projected zigzag line and the face of the brush as the first and second references to define

the plane, just as you see in the image. A plane will be created, tangent to the surface and

coincident with the point selected.

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21. The next four reference planes are created in a similar way…

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22. Select the first reference plane created in the previous step (Plane2) and open a new sketch on

it. Draw a 0.04 in diameter circle centered on the origin (the point at the end of the curve). It

may be necessary to add relations to make sure the circle is indeed centered at the end of the

curve.

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23. Use Extruded Cut and the circle you just sketched to create a hole 0.09 in deep. Repeat steps 22

and 23 for each of the remaining reference planes. You should end up with five holes evenly

spaced along the left side of the projected zigzag line.

24. Use Mirror to create a copy of the first four holes. Mirror the four first extruded cut features

about the Right plane, as shown in the image.

25. Now create a linear pattern, just like you did before. Pattern the five extruded cuts plus the

Mirror feature from the previous step. Use the vertical construction line of Sketch5 again to

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specify the direction of the pattern, a spacing distance of 0.43 in and a number of instances of

nine.

26. Now create a new linear pattern, but this time as features to pattern select only the four

extruded cut features that you see in the image. Use the vertical construction line in Sketch 5 to

specify the direction of the pattern again, but reverse the direction to pattern, as you see in the

image. Use a spacing distance of 0.41 in and a number of instances of two.

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27. Use Mirror to create a copy of the pattern from the previous step. Mirror the linear pattern

feature about the Right plane. Check the option Geometry Pattern. I’m not exactly sure why, but

the Mirror feature will give you an error if you leave this option unchecked.

28. Go to Reference Geometry, Plane and create a new reference plane 0.6 inches from Plane 1, as

you see in the following image.

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29. Open a new sketch on Plane 7, the plane you created in the previous step, and draw an ellipse

centered at the origin. Use the dimensions from the image.

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30. Create a loft (Loft feature in the Features toolbar) between the sketch from the previous step

and the edge of the brush, just like you see in the image. Use Normal to Profile as a constraint

for the sketch (Start Constraint) with a tangent length of 0.57 in, and Curvature to Face as a

constraint for the Edge (End Constraint), with a length of 0.43. Actually, you can play with the

valued of the length for both, the sketch and the edge, until you are satisfied with the way it

looks. If the surface in the preview appears to ripple or buckle then it probably means you need

to use a smaller value.

31. Open a new sketch on Plane 7 and use Offset Entities to offset the edge of the brush a distance

of 0.03 in, as shown in the image. Use Extruded Boss to extrude this sketch a distance of 3.5

inches to create a handle for the brush.

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32. Use Dome (Features toolbar) to create a nice little dome at the end of the handle. Use a

distance of 0.3 in and make sure to un-check the option continuous dome, to keep it from

turning out pointy.

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33. Go to Reference Geometry, Plane and create a new plane 0.03 in from Plane 7. This is Plane 8.

34. Open a new sketch on Plane 8. Use Convert Entities (Sketch toolbar) and select the edge of the

handle and Sketch 14 (created on step 29) as entities to convert. The result is a couple of ellipses

that we’ll use to create a cut in the handle.

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35. Use Extruded Cut and the sketch from step 34 to cut a distance of 0.06 in, as shown in the

image.

36. Create a new linear pattern. Use the same vertical construction line from Sketch 5 to specify

direction. Pattern the Extruded Cut feature from step 35. Use a spacing distance of 0.09 in and

30 instances.

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37. On the Top plane, open a new sketch and draw a circle like the one in the image below. Use it to

extrude a cut through all in both directions.

38. Open a new sketch on the Top plane and use Convert Entities (Sketch toolbar), select the sketch

from step 37 as the entity to convert. Then use Offset Entities (Sketch toolbar) and offset the

circle you just created by converting the sketch a distance of 0.06 in. The result is a couple of

concentric circles separated by a distance of 0.06 in.

39. Create a boss extrude using the sketch from the previous step. Under Direction 1, select Offset

from Surface. The surface is the face of the handle that appears in pink in the image. The

distance to offset is 0.03 in. It may be necessary to check the option Reverse Offset and to

change the direction of the extrude. Do the same for Direction 2, until the preview looks like in

the image below.

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40. On the Top plane, open a new sketch and draw a vertical line. Use this line to create a slot, using

Offset Entities, just like we did previously.

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41. Create an Extruded Boss feature using the sketch from the previous step. Under Direction 1

select Offset from Surface and select the face shown in pink in the image as the face to offset

from. The distance is 0.04 in. It may be necessary to check Reverse Offset and change the

direction of the extrusion until it looks like the preview in the image.

42. The body of the hairbrush is now complete. If you followed the steps correctly, you will now

have something that looks a lot like this.

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43. Save the part and then create a new assembly from the part (File, Create new assembly from

part). The bristle part is provided. I won’t go into detail on how to model the bristle because it’s

very easy to make by revolving a sketch. Insert the bristle part into the assembly; you’ll need 9

instances of it. Position each bristle inside the holes of the second row of holes in the brush

using a concentric mate between the cylindrical faces of the bristle and the hole and a

coincident mate between the bottom flat face of the bristle and the bottom flat face of the hole.

The result should look like the image.

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44. On the Assembly toolbar, select Feature Driven Component Pattern. Under Components to

Pattern, select the bristles you inserted in the previous step. Under Driving Feature, select the

linear pattern LPattern2 from the features in the hairbrush part. Select it from the fly out

Feature Manager. The bristles now populate each of the holes in the linear pattern.

45. Repeat the procedure from the previous step to create a new feature driven component

pattern, but this time select only the seven bristles shown in the image as the components to

pattern and LPattern3 as the Driving Feature.

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And that’s it! If you followed the instructions correctly, you should have something that looks just like

this brush here.