circular patterns of holes and parts

[PJK13]

Hi, I have two questions regarding the circular pattern.

Does anyone know how to:

1. Create a circular pattern of parts. For example to bolt a lid on to a cylindrical vessel can I put a bolt into one of the holes and then copy it around?

2. Create a circular pattern of holes. I am trying to create a cylinder with many holes equispaced around its circumference but all being drilled towards the centre of the cylinder. I drew one hole using a plane on the cylinder surface but when I copied it around the copied holes were pointing in the same direction as the first and not towards the cylinder axis.

Cheers,

Pete.

 

[MadMango]

Answer 1) You first have to define the holes in the flange using the Hole Wizard. After that, you can use component pattern to copy a bolt, using the hole pattern as a reference.

Answer 2) After your first feature cut of the hole, you have to select the center axis of the cylinder to pattern the holes around the cylinder. "The attempt and not the deed confounds us."

 

[RawheadRex]

Pete,

I would like to expand a bit on MadMango's reply to give you a bit more detail on how to accomplish what you want to do.

1. Place a hole in the model of the vessel/flange (using Hole Wizard is the best method). Next you want to pattern the hole you just created in the Part model around an axis. Then insert the bolt into an Assembly model containg the vessel/flange and mate it into the hole. Now create a component pattern in the Assembly model using the bolt and the pattern feature from the Part Model.

2. When placing a hole on a cylindrical face your best bet is to use the Hole Wizard. This will put you into 3D sketch mode in the Part model. Create a coincident relation between the sketch point and the surface of the cylindrical feature and then define the axial and radial location according to your needs. Once you've created the first hole, rebuild and generate a radial pattern using the center axis of the cylindrical feature to define the direction. That ought to take care of you.

One additional note regarding placing holes on cylindrical features. I've found it's much better to use the Hole Wizard in these instances rather than to create planar geometry to locate the hole. The planar method is a significant amount additional work to generate and modify. If you're not comfortable with 3D sketches it may seem easier to go that route but you're better off spending some time getting the hang of 3D sketch mode if this is a type of geometry you're going to need to create often.

Chris Gervais
Mechanical Designer
American Superconductor

 

[SnowCrash]

Rawhead Rex has it right. There are a couple of points I would like to emphasise.
You need the axis. It needs to be on the center of your eventual pattern. You need to set view so the axis is visible.
If you have a vessel and a flange then locate one of the holes sets as a pattern, frinstance, the holes in the flange. The holes in the other part should be driven off of the patterned holes as multiple points in the hole wizard sketch. They do not need to be another pattern.
Color the surface of the seed hole in a contrasting color so you can find it when you need to make the fastener pattern.
Place the first instance of the fastener [group] in the seed hole. Ctrl-click select the axis and all seed components that will be in the pattern, then select the component pattern tool from an icon or the menu.
You can add or delete items from the pattern by redefining the pattern.

Crashj 'wheel like a heart' Johnson

 

[APPENG]

There is an easier method

If you created the holes in the flange using a circular pattern you can place a bolt in the "seed" hole The one that was used to make the pattern

then afterwards using component pattern, you can specifiy to use an "already existing pattern (derived)" then select any of the other holes in the pattern.

The bolt will not be in the rest of the holes.

Much much simpler

hope that helps Regards,
Jon
jgbena@yahoo.com

 

[RawheadRex]

"If you created the holes in the flange using a circular pattern you can place a bolt in the "seed" hole The one that was used to make the pattern

then afterwards using component pattern, you can specifiy to use an "already existing pattern (derived)" then select any of the other holes in the pattern."

I think that's what I said already, repetition is a good thing though.

Chris Gervais
Mechanical Designer
American Superconductor

 

[drawoh]

Here is another thought everyone! What happens when you define your polar array with fasteners, and someone comes along and insists that you key it by making one of the angles not equal to the others?

Killing people like this is illegal, and it makes a mess all over the office

I believe in the hole wizard. I want to be able to easily modify whatever it is I have done with the hole wizard.

* Launch the hole wizard.

* Specify your hole.

* In the sketch, use the polygon tool create reference geometry that you will use to locate the hole points. You need a polygon corner for each hole. You will have to convert the straight line sections into construction lines.

* Locate each hole on a polygon corner.

* Finish the sketch.

* Insert the first set of screw, washers and nuts.

* Define the assembly pattern, using your wizard-defined hole. This is WHY you use the hole wizard, although arrays work too.

This is a little more work than using an array, but it is now easy to modify the pattern. You can change the angle spacing. You can move one or two holes off the pitch circle. You can add or delete holes, since the assembly pattern updates automatically.

JHG