Is high-quality tooling with quick aluminum extrusion possible?

As most of you know, quick aluminum extrusions are great to save design and manufacturing time, but have some downside in term of quality level and durability (screws tend to losen-up overtime) (see "Design A" as typical quick extrusions and bracket that can be bought on McMaster)


In "Design A", positioning of the 90' bracket in the groove is done by a "straight locator" creating a slack of 0.025


In "Design B", positioning of the 90' bracket in the grove is done by a "tapered locator" eliminating the slack as the srew is tighten.


Do you think that if "quick extrusions" were done like "Design B" we could do high-precision tooling with them?


Thoughts?[IMG]http://www.engineersedge.com/engineering-forum/attachment.php?attachmentid=1707&stc=1[/IMG]

[quote][COLOR=#333333]Do you think that if "quick extrusions" were done like "Design B" we could do high-precision tooling with them?[/quote]
Possible however the tapered surface contact would likely create inaccuracies vertically..


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Yes it's true but the purpose of this part is not to be well positioned vertically but only in the lateral direction. the other two directions slides to the desired position. We want to know if have [COLOR=#333333]"tapered locators" can bring an advantage to [/COLOR][COLOR=#333333]do high-precision tooling.[/COLOR]

My experience is that those angled surfaces will cause more problems than they will solve. They allow too much variation. To give any better response will require a more precise description of what you are trying to accomplish. I have seen extruded aluminum used to create some precision surfaces, but it is not an easy thing to do and will require exact definitions of your goals. In general I would avoid it.

I don't see any advantage to the tapered extrusion..

One problem with tapers is that during seating one side may stick while the other slides and result in an angular lateral displacement of the upper part.