Need an advice. Press consrtuction.

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motoman
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Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Need an advice. Press consrtuction.

Post by motoman »

Dear members of this unique web resource,
I am going to produce snowboards in small amount.
Having read a lot of information here I came to the conclusion that I beam press is most popular.
I have attached a few drawings of I beam section and general view of future press.
Also I have some questions for people with experience.
I know that welded I beam is not that good as cast one, so I will use last one. Also I am going to use bolts instead of welded joints for better demolition in future. Is the usage of bolts is suitable?
The main question is about deflection. What do you think about chosen cross-section? Is it reasonable to make it smaller of bigger? The section have to withstand 80 psi. Am I wrong?

motoman
Posts: 243
Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

I will add pictures soon, as it is my first day as a member of this forum.

Richuk
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Post by Richuk »

Greeting )

Just need to checked whether you have seen Chrismp's press. Quite possibly the most effective design - just missing a thermal cover )

Enjoy:

https://vimeo.com/60566948

And there are a couple of factory video's with this type of press design:

http://skibuilders.com/phpBB2/viewtopic.php?t=3173

- Kingswood
- Crisp Custom
- and one of the big boys (they can be seen in the background), I just can't remember which video it is.

motoman
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Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

This information is precious!! Still can't upload my pictures((

motoman
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Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

Image
Image
Image
Image
Image

motoman
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Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

Who can tell me, what is allowable deflection in the middle of the beam?
The materials in my country are really expensive now. I would like to choose the cheapest way to construct my press.
I have applied the force equal to 80 psi to the bottom and to the upper part of the press. Is it right?

PS all dimensions are in millimiters ( 1 inch = 25.4 mm) (2500 mm = 98.43")

Thank you in advance

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vinman
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Post by vinman »

Put a fixed center post in the back of your frame and a removable post in the front an re-run your simulation. Those bars on the top of your frame aren't doing anything to prevent deflection.

80 psi might be high, 50-60 is more typical of what most of use.
Fighting gravity on a daily basis
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motoman
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Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

you mean I have to put some bar or other steel profile in order to reduce deflection of upper beams? This bar will work on tension.

Could you tell me, what is limit deflection value of beam? As I know deflection effects on the process of compression of boards or skis.

Prak
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Location: Milwaukee, WI

Post by Prak »

Watch the Kingswood video closely at 4:42
https://vimeo.com/11913875

Also, Falls' press (minus the locking handle):
www.skibuilders.com/phpBB2/viewtopic.ph ... 1&start=30

I'm glad this was brought up, as I've been meaning to ask, does anyone know what kind of locking mechanism Kingswood used for the handle? At first, I thought it was just mechanical, but if you pause the video at 4:50, it appears the handle may be locked in place pneumatically.
Edit: Upon further review, it appears as though the pneumatic system touching the handle could be some sort of valve that will only allow the bladders to inflate if the handle is locked in place.

Any insight would be appreciated.

motoman
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Location: Ukraine

Post by motoman »

I have seen this Kingswood video before, it is good idea to use less metal and reduce deflection to the minimum. It seems to me than 0.1" is not big value.

after turning the handle mechanism closes. ordinary lever.

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richie
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Post by richie »

My design is very similar.

I used 360UB50.1 universal beam , which is 360mm deep and from memory the web is only 6 or 7mm thick and the flanges approx 175mm wide x 12mm thick. So just a little bit deeper beam than you are proposing.

My press beams are 2.5 metres long. 2 on top 2 on the bottom so its 350mm wide. using small section of UB at each end as the separating section between top and bottom beams.

Bolted together with 32 of 25mm 8.8 HT bolts, 8 per joint.

For curiosity , I tested up to 120psi my full compressor output and the was negligible deflection like 1-2mm I am pretty sure, and that was with the twin air bag hoses laid flat and well packed so they were getting maximum surface area bearing on the profiles. Of course I stood well back while I did this!

My theory was build it with what I could find locally available, the bolts were $1 each I stumbled accross them, so no brainer use them, maybe I coudl have used smaller but thats what popped up. Same with the steel beams I looked at typical presses and found some similar steel, on the big side so I assumed it was safe. The maths is too complex for me so I just went bigger with my gut feel.

I love my side loader press and wouldn't do much different if I ever built another one.

The "clamshell" upgrade with heavy hinge at one end and locking pin at the other , with air rams to lift/hinge up the top beams, was the key to super easy loading. with this I can quickly and precisely load the ski/board cassette without having to wrestle the gooey layup cassette into a tight slot. Same as the presses with the bottom jacks to liftt he bottom beams its so good to have the clearance when putting the cassette into the press. Some people don;t find they need it but for me as a one man band I find it super helpful. I'll try find a pic to post.

Image

cheers
Rich
MonkeyCAM and SnoCAD - https://github.com/mikemag
Ski binding mounting https://github.com/splitn2/DrillSki

Richard Harcourt | www.splitn2.com | Christchurch New Zealand
rich@splitn2.com | www.facebook.com/splitn2

motoman
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Post by motoman »

Great device!!! I'm impressed. Thank you for the description!! Hope, soon, I will post pictures of my own press here!!

Richuk
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Post by Richuk »

Dude.

Quick, easy and cheap to make aka: Mongo style press.

http://www.skibuilders.com/phpBB2/viewt ... e0ef4a5464

The best example has been built by Chrismp.

You need to look at his press in terms of effective control of the cure cycle. A thermal cover would help this design, as it would retain the heat, reducing costs. Once enough heat has been applied, remove the cover and the lack of physical mass ensures the mold cools quickly and at the required rate. This means you have effective control over the cure cycle.

Deflection of the bottom mold is the only issue you should be concerned about ... subject to safety considerations.

An I-beam press is fine - until the rent goes up, or you need to make another. Do you have the engineering, fabrication skills to make a mongo style press?

motoman
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Location: Ukraine

Post by motoman »

Mongo style is not that complicated. I think I can perform this work. But the only thing that disturbs me is bolts. Somewhere I have seen that under high pressure they can be deformed as they work on shear.
But in general this is good and cheep variant.

Richuk
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Joined: Sun Jan 31, 2010 9:53 am
Location: The Duchy of Grand Fenwick

Post by Richuk »

The Mongo press was just the starting point (as far as I am aware). I would be cautious with the design - too many issues

Have you're head around this thread:

http://skibuilders.com/phpBB2/viewtopic ... c&start=15

You want to contain the pressure using an external frame work - per the press shown by Chrismp in his video. Yes - shearing a bolt would be a bad thing. So its a matter of using the right bolts and the correct thickness of steel.

The Mongo press has no safe guard in place for the failure of a weld.

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