Part Placement 2

[Laurel]

This is probably another simple problem, but it's one that I'm stumbling over.

The attached drawing shows the back of a 'Z' extrusion and a flat extrusion. The dimensions shown are on a visible sketch. The lower edge of the 'Z' is constrained to the upper face of the flat piece.

I want to contrain the 'Z' further, so that it is positioned against the 25mm line shown on the sketch. Up until now, my training has focused on constraining the faces of parts, but that doesn't appear relevent in this case. (I can't get it to work, anyway!)

Any help would be appreciated.

[JD Mather]

Not sure what you are after based on your description, but you can also constrain edges. Zip and attach your file if you have trouble figuring it out.

You might also want to go through this document before you pick up too many bad habits http://home.pct.edu/~jmather/AU2007/...L%20Mather.pdf

[Laurel]

Thanks JD, here is the project, zipped as requested. We are concerned with the assembly file.

I want to position the part labelled 'Z Section' so that it is in the position indicated by Sketch1. This sketch is only there for the purpose of this post, and is not part of the final assembly.

As far as I can tell, there are no edges or faces that will align in order for me to use a constraint.

BTW, what bad habits have you noticed?

[Laurel]

It occurred to me (during a period away from the PC) that if this assembly were designed with mechanical fixings forming the joints, there would be holes in both extrusions for me to constrain to. This is not the case here, as the parts are to be welded.

This led me to realise that instead of assembling these models as seperate parts on the assembly drawing, perhaps I should have modelled both the extrusions (and the intended joint) as one part. Maybe this is the bad habit you are talking about JD?

However, just because these parts are welded and not bolted together, shouldn't mean that I can't still assemble them as I have indicated should it?

Is there never a situation where a part needs to be placed in an assembly in a position that relies on measurements, and not constrained edges and faces?

[JD Mather]

At least two methods (I'm sure more).
Easy - Mate Flush and type in Offset distance.

Hard. Add sketch line for edge location on mating part and create Axis with the line. Then constrain edge of second part to axis.

and a third method (I knew there must be more)

...learn Skeletal modeling techniques (AKA Master Modeling) and don't have to worry about constraints at all. In combination with Frame Generator this looks like perfect application.

BTW model as separate parts (2010 supports multi-body parts) if you intend to add weld beads or represent the real world.

[Laurel]

Thanks very much JD.

I don't know why I keep overlooking Mate Flush, but this isn't the first time. As a new Inventor user, I'm very happy with the progress I'm making, but I am yet to remember all the procedures that I need.

I'm sure I'll be back for more advice shortly - Watch this space.

[JD Mather]

I don't know why I keep overlooking Mate Flush,..

Mate face to face would also work but use different faces and offset magnitude. Use the logic that is important for aligning the actual parts when assembled.

I am yet to remember all the procedures that I need.

I've been certified as an expert since release 7. This week I am preparing to teach a 2010 update class on Friday. I've given up on pretending I will know all of the new stuff in time. Heck I'm still finding old stuff I didn't know was there.

Looking at what you have done so far looks like you are doing very well. You will want to investigate the Frame Generator though. There is a tutorial under Help>Learning Tools.

[Laurel]

Thanks very much JD. All your advice is very much appreciated, as always, and a bit of encouragement is always nice to receive.

I'll look forward to looking at the tutorials you suggest when I've finished my current college assignments.

Thanks again.