www.TK560.com

[trophy]

I am curious as to why there are vac holes all over the platen and not just under the part being formed.
I am of the opinion that the holes outside the shape hold the plastic down too tight and do not allow the plastic to slide a toward the shape, thus reduce thinning on vertical sides.
Very interested to hear your views.

[cod]

there are more than a few folks who just use one hole in the middle. Either way will work. There is something to the idea that multiple holes works well when you are forming multiple parts on one platen. A single hole is easier to construct and seal.
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[spektr]

IMHO, IF YOU USE A PLATEN PLENUM COMBO, holes all over the platen work better than a central hole.
Central holes require the model to be raised off the platen surface with a spacer like window screen or popsicle sticks or even thumbtacks stuck into the bottom of the model/tool. This means that the effective vacuum oriface size for pulling the job is roughly the mold/tool perimiter distance in inches, times the gap height. Having holes all over the platen means that it is a lot more difficult to prematurely seal off the work before it seats on the tool and having incomplete pulls.....

BUT in fact, my machine has no platen. I use seperate tool bases for each part I make. The problem I have with platens is the plenum volume you need to pull each time you pull a part, and the lack of sheet optimization that occurs when we get lazy. Also, it is much easier to control a smaller sheets temp across its face than a larger sheet.

[ANH trooper]

I have tried both multple and sinlge hole platens and have to say the single ROCKS! No need for adding spacers, I simply add two layers of mesh screen and pop on multiple moulds and get perfect pulls @-30"hg every time.

I will say though that when I had the multiple hole platen, it was made of wood and not aluminium like my single hole platen, so I doubt I was getting a perfect seal. Other members who had the multiple hole platens have switched to a single hole platen with no regrets

[spektr]

I can hardly wait for you guys to get away from the platen and go to seperate mold bases. The only thing you need then is a seperate clamping frame for each blamk size you wish to run. A minor issue, but you save a lot of p[lastic this way.....

[trophy]

I am very curious as to how you are doing this, can you post a pic please.

[spektr]

I'll send a picture as soon as I figure out how to do it. The reason I do it is to stop wasting plastic. I might run between 10 and 250 of an item at a time and trimming a bit of waste makes a large difference to unit cost.. I run in a production environment, not a prototype world where plastic cost is less of a concern........ I also look at all the different sheet sizes available and do layouts to maximise sheet yeilds.... Just because 2x4's and 4x8's are common doesnt mean that 75 x 100, 5 x 8, 6 x 8 or a custom sheet might not be better. Scott..

[ANH trooper]

To post an image, first you must upload the image to somewhere like 'photobucket' or 'imageshack'. Then, in your reply, click the box marked 'Img' which is below the subject box, and the image tag will appear. Simply copy and paste the image tag from your hosting site next to the image tag and then press the image tag again to close it. Press 'Preview' to see if it worked properly (which it should do ) then press 'Submit' and your done.

Looking forward to seeing what you are doing!