www.TK560.com

[VacFormer]

I am strongly considering going this way, I like the setup. I have also seen a machine from steltercreative.com and its very similar but with automatic frame raiser functionality. Making the machine a bit smaller in terms of height..

I will have the machine in our basement and the ceiling is not very high - 6.6 ft..

So my question is if the ceiling is too low for this type of machine - also for safety reason - leaving space on top of the oven..

What would you say?

[stormtrooperguy]

My basement is about the same height.

I had to adjust the plans slightly, but it works fine.

I took the wheels off, and lowered the height of the mobile cart by about 4".

This leaves a good 15" - 16" between my ceiling and the heater. I was using the table for about 4 hours last night and the ceiling wasn't heating up at all.

That being said, I'm still putting hardibacker up on the ceiling, just to be extra-safe.

The biggest thing is making sure the handle for the plastic carrier clears the ceiling. You need to be able to lock it in place overhead, which requires a lot of clearance... probably 14 - 15"

[VacFormer]

Thanks for the input! Really appreciate it!

I know that the bar for the frame needs some hight to go above the oven and that is why I think it would be cool to combine the protoform with the stealtercreative's regarding the automatic lift. But of course I will still need the space on top for circulation..

Already love my new project!

[VacFormer]

Been measuring my basement again - the ceiling height is my challenge.. What is the minimum space on top for ventilation? Would 10 inches be safe if I also use some material to avoid heat on the ceiling?

I would hate the table to be too low - else I have to dig out the floor to give some extra 10 inches!

[jdougn]

The ProtoForm oven is designed to come on only when you're heating plastic. When I heat 1/8" ABS the top of the oven will only get to a couple hundred degrees fahrenheit right on the oven. The sides of the oven never get over 100f, if that much. I would think that 10 inches of top clearance would be more than enough. A cooling fan could be added, or insulation to the top of the oven, to reduce heat build up.

Actually, consider some type of ventilation fan too. The fumes from the heated plastic could be a problem. I've only worked with ABS, but it gives off heavy odor and sometimes smoke, especially if overheated much at all. Look for a way to ventilate a lot of air straight outside.

Look over the plans to consider modifications for your height situation. Modifying the base would be easy. Modifying the plastic carrier lifting mechanism would be more difficult. The way Doug Walsh designed the geometry for the lifting mechanism is amazing. Then I would suggest calling Doug Walsh. He is working with some ideas for mechanical lifters for the plastic carrier. He might have some good suggestions. At the very least be aware that the powered lifters will have to be carefully synchronized. Also, if the mold is not perfectly centered (and it never will be) then the plastic carrier could try to jam from the off-centered forces.
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DougN - Just in case you're wondering, I got my "rating" legitimately... by posting aimless drivel, useless advice, and pointless questions.

[VacFormer]

Thanks for the input Doug!

I am pleased to hear your input regarding the hight of the oven - Some good advice! I will make a fan system to cool the top of the oven down and also put some fireproof plasterboard on the ceiling.. That should do the trick I hope!

Since I will be working out of my private - the basement - I want some kind of ventilation system to reduce the fumes from the plastic..My wife would be angry!! I hate wearing the mask so the more ventilation the better I guess.. I will place the machine close to an existing window and then make a nice little system to lead out the fumes..

I have started reading the ProtoForm plans and I am amazed of the details and skills gone into to this.. However I want to optimize on the raising mechanism - to get the best possible hight of the oven.. The steltercreative looks great, but I guess it is an expensive solution using those kind of lifts.. Any advice on where to get to cheap pneumatic cylinders?

In case you havent seen the video on youtube - here it is:

http://www.youtube.com/watch?v=ZgvLjkLTet4

http://www.youtube.com/watch?v=7XPeSn23tuE&feature=related

[stormtrooperguy]

I just measured, and for the protoform arm to lift up properly, 12" is the minimum height over the top you need, and that JUST clears it. More space would be better.

So to avoid messing with the linkage / carrier frame piece of things, you can just shorten the height of the mobile cart accordingly.

I built a vent hood into mine.

There is a 160 CFM fan vented straight outside in the wall behind the table. I built a sheet metal cover that connects the table to the wall over the fan, so that smoke / fumes have less places they can get away from the fan.

So far, so good... the longest work session I've had has been 4 hours, and the house didn't smell

[VacFormer]

Thanks again for great input - I really appreciate it!

I have been through the plans again and I am pretty sure that I want to go for the the following setup:

2 x 3 setup -
Two zone heating -
Two Platens - (2 x 3 and 2 x 2) -

I wil go for the manual setup - been talking to Doug and he doesnt recommend the pneumatic cylinder lifts - too expensive and too much tweaking ongoingly..

I think I will be using the "2 stage vacuum System" as described in the plans..

I will go for the following in terms of pump and tank:

35-40 gal. tank and 10-17 CFM pump.

My questions now is do the large platen requires two pipes for the vacuum system or can I stick to one? Also taken the 2 stage vacuum system into account..

What do you guys think?

[spektr]

if you are actually using a 10 cfm pump and that big a tank, dont mess with the 2 stage system.. it is a crutch not having a big enough tank and pump.

[VacFormer]

Cool - thanks for the hint! I will leave it without the two stage!

[kayaker43]

Spektr is right, those pump and tank sizes are good for a single stage system. This will equal any good commercial machine and will be more than adequate for any costume armor. If you build a good platen, use the right pump and convert it to a two stage system you will be able to finish off with 29 inches of vacuum. That's above and beyond what commercial machines can offer and not everyone needs that. Start simple but know there's more performance available if needed.

Pneumatic cylinders can be made to work but I don't reccomend them. Air is compressible so they act like springs. You can match the speeds with needle valves but they always seem to drift and need tweaking. Any binding will cause the frame to cock and jam. An off center mold will cause problems. Its been done many times but its not a robust solution. One tip is to resrict the outlet of the cylinders instead of the inlet to control speed. This firms up the spring effect somewhat but its still a marginal idea.

Ideally you want to transport the plastic in one second or less, then decellerate it and apply a good amount of force at the end of travel. Its hard to beat the human touch here but a motorized method is pretty good if you can work it out to also have a good synchronizing. For the sizes I sell, a manual linkage simply works the best. 4 x 4 and larger needs some power assist.

The Proto-Form oven has a lot of thought and testing into the oven venting so the outside of the machine stays cool. Don't add insulation or change the design. You may be able to shorten the handle a bit to reduce height and whatever clearance you need for the handle is enough for ventilation.

Room ventilation is important but don't create air movement across the plastic while heating. A warm room and calm air are essential for even heating.
_________________
Doug Walsh
www.build-stuff.com
Hobby-Vac and Proto-Form machine plans

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