[PSUBS-MAILIST] Program

Fri Oct 23 09:04:39 EDT 2015

I seem to recall Phil saying that his segments were pressed once on centre, and then repositioned for a few hits around the edge to ensure sphericity.

I haven't actually been down to EE to see their equipment. I'm having difficulty visualising why the die change is necessary.  Also, did you supply a drawing / tolerance limits? 

What is the thickness, and how much thinning was there on the pieces supplied?

Sean

On October 23, 2015 4:17:36 AM MDT, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>Sean,The heads were supplied as perfect hemis, with the edge beveled.
> The defect is about 5 inches from the weld.  I will send another
>photo.Hank 
>
>
>On Thursday, October 22, 2015 9:30 PM, Sean T. Stevenson via
>Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>   
>
>Were your heads supplied as perfect hemis, or with a length of flange?
>Weld prep? How close to the rim is the defect? A photo would help.Sean
>
>
>On October 22, 2015 6:05:19 PM MDT, hank pronk via
>Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>Sean,This is a new project,  and I am exploring this option because of
>the imperfection in the pressed heads I got for my pod.  EE told  me
>they can not press a smooth head without this imperfection.   The
>imperfection does not go away until a thickness of 2 inches.  The
>problem stems from changing the die's.  My plan is to have the pieces
>cut and pressed and will fit over a head that I already have, the head
>I have will be cut to act as a jig.  My preference is to use two semi
>heads of coarse, but I am concer! ned overthis wrinkle in the heads.  I
>could overlay weld and grind smooth as the imperfection is    quite
>shallow, maybe 1\16 in.  other than this wrinkle, the heads are deadly
>accurate.I will post a picture of the imperfection,  
>
>
>On Thursday, October 22, 2015 5:11 PM, Sean T. Stevenson via
>Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>   
>
>For segmented construction, instead of full hemisphe! res, youonly need
>dished heads of the same radius as your sphere and sufficient diameter
>to encompass all of the vertices in the segment.I would refer to this
>as a "dished-only" head, and am unaware of other industry terms. Of
>course, you only really get the benefits out of segmented construction
>when you have good control over thinning, and pressing is preferable to
>spinning for that reason, if your press can accommodate your required
>diameter.Sean
>
>
>On October 22, 2015 5:02:45 PM MDT, "Sean T. Stevenson via
>Personal_Submersibles" <personal_submersibles at psubs.org> wrote:
>What are you making?As I mentioned, the DW hulls are segmented
>according to a cube projection, so a complete sphere would have six
>segments / sides and eight vertices, and three times the welding (and
>subsequent 100% NDT inspection) that two hemispheres would require.You
>need a template for cutting, and an accurate jig for welding them
>together.Did you get hemispheres supplied out of spec? Or is this a new
>project?Sean
>
>On October 22, 2015 4:15:08 PM MDT, hank pronk via
>Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>Sean,Do you know how many sections a DW hull has and what is the
>technical name for what I want to do.  I will ask EE if they will make
>the pieces. I think Dr Nuytten calls them woks?  I want to sound like I
>know what I am talking about :-)Hank 
>
>
>On Thursday, October 22, 2015 12:27 PM, Sean T. Stevenson via
>Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>   
>
>That's just a construction. Any regular polydehron that fits in your
>sphere can be used as a guide. Nuytco uses a cubic projection, so if
>you imagine a cube where all of the vertices touch the sphere, the weld
>lines are the great circle routes between vertices.If two hemispheres
>don't work for you, the next lowest part count you can go to is four,
>corresponding to the tetrahedron projection.Sean
>
>
>On October 22, 2015 11:49:51 AM MDT, hank pronk via
>Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>| Sean, do you have a program that will disect a sphere into equal
>sections like the DW. I am looking for a way to cut hemis into equal
>sections to create a new sphere. When we buy heads they have full
>cerumference dent caused from changing the dies. I am thinking about
>buying three heads to make one perfect sphere. |
>
>
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