FP HW Tips

[wazio]

What is the normal set up for a UK HW FP flipper? A few others and myself are thinking about building a HW for the flipper upcoming BB event and are wondering what you guys use in the big bots€¦


Also, I wanted to see what you guys have to say about the argument on solenoid valves to control the ram Vs. a low pressure operated ball valve to open the thing super quick.


Thoughts, comments, suggestions, pictures..?.. Woody, Mario.?.?.

[woody]

FP HW Tips

Mario advocates multiple Burkerts ...you get a quicker instant flow.
I believe that a ball valve setup is just as good ...if not better.

Your flow or Cv / Kv requirements depend on your ram volume , leverage ratio and mass to move.

[maddox]

FP HW Tips

Woody, the multiple burkert setup has other advantages.
1)No low pressure needed in the machine, what eliminates the need for a regulator -a thing that cant handle liquid CO2-(and in the UK FRA rules, the multiple PRDs)
2) Straigth from the box solution. Buy Burkert 5404 valves and you dont have to build controling parts for the ball valve. The only thing needed for a sure function is 36V to control the solenoids.
3) Space and weight needed. Compare a 1 ball valve with controling piston, control valve, hoses, connectors and regulator to 4 burkerts set aside. (this is overkill for a 4 bore ram)
4) Pricetag if everything is bought new. All the low pressure parts add seriously to the cost.

But Chad, if youre not on a budget, or have acces to CNC machines, A Woody 3/2 or 5/2 valve with Maddox control soleno¯d is the best of all worlds. (TAN and Ka-Put use these)
No size restrictions at all, instant opening, no LP setup needed, and best of all, lightweight compared to KV

[woody]

FP HW Tips

Multiple Burkerts will of course require multiple ram inlets and associated pipework.

You can get an idea of your max required Cv from these two calculators.

http://www.wa4dsy.net/robot/flipperhttp://www.wa4dsy.net/robot/flipper
and
http://www.proautocon.com/tools/pac_cylsizer.xlshttp://www.proautocon.com/tools/pac_cylsizer.xls

Quick example using a 6 x 6 ram @ 750 psi

Force generated by ram approx 21,000 lbs

At a 1-1 ratio ...220lbs sitting directly on the ram ... your optimum ram extend time from Dales calculator would be 0.018 second.

Throw that extend time into the cylsizer ... use 6 bore 6 stroke and 6 rod dia plus a pressure of 750 and drop of 10 ... and you get a required Cv of 197!

Increase your ratio to 6-1 and the force at the flipper tip decreases to become 3500 lbs and flipper tip travel increases to 36... the ram extend time then increases by a factor of 6 to 0.11 sec.

Throw this new extend time into the Cylsizer and you get a required Cv of 32 ...or 1/6 th of the original 1-1 calculation.

All the above calculations are just Math and in practice youll get nowhere near the throws shown.

Id be tempted to go with a 3 way T Ported ball valve of around 1 or more with the above 6 cylinder @ 6-1 flipper ratio....it also gives you a built in ram exhaust valve.


You also might want to consider using the 1 60 bar Jaska valve listed here.... http://www.jorc.com/catalog/us1415.htmlhttp://www.jorc.com/catalog/us1415.html
with a flow 5 times that of a single 1/2 Burkert as an inlet valve.

So many choices ...

EDIT ..Another alternative could be a self venting ball valve....thus combining inlet and a small exhaust in one unit.



(Message edited by woody on May 07, 200

[m2xt]

FP HW Tips

No question in my mind, ball valve for performance - see http://www.technobots.co.uk/M2XT/M2XT-Home/M2XT_Build/Pneumatics/body_pneumatics.htmlhttp://www.technobots.co.uk/M2XT/M2X...ody_pneumatics .html

[Mouldy]

FP HW Tips

for the weight of 4 burkets you mayaswell go for a 1 ball valve and a small ram to operate it. In my opinion its been proven to give a way better flip then any burket powered machine. Hence the new M2 and the new Iron Awe.. also i believe the big american bots used ball valves, toro, the matador, t-minus etc.

[woody]

FP HW Tips

Chad ...A fully OPEN 1 full bore ball valve will have a flow equivalent to 10 or more Burkert valves.

[leorcc]

FP HW Tips

With those kinds of flow I doubt you will get more than 1/8 of the ball opened before the ram is extended fully.

[maddox]

FP HW Tips

Of course Woody, the Burkert has 2 90° angles to pass, the Ball valve is straight trough.

But, the ball valve wont be fully open before the ram has reached end stroke.

[john]

FP HW Tips

i asked my dad abit ago and he said what mario just said

the ball valve wont be fully open before the ram has reached end stroke

though what iron awe is going i would do as that robot is one of the best flippers around

[woody]

FP HW Tips

the ball valve wont be fully open before the ram has reached end stroke

Are you sure?

OK ...What is the opening time of a 1 bore 3 stroke ram when supplied with 150 psi by a std 1/4 port 5/2 valve with a Cv of around 1.2?



The ram setup I suggested had a LOADED opening time of 0.12 sec... So...

BTW ..What is the opening time for a Burkert ?




(Message edited by woody on May 07, 200

[maddox]

FP HW Tips

Burkert gives a responce time of 0.05 seconds.

[wazio]

FP HW Tips

Hehehe, this is exactly what I wanted to see two different views on things and reasons to back them€¦

I like the simplicity of the solenoid valves, on and off, easy to set up and wire, however I don€™t really like the amount of tubing, size and fittings that will be required.

I like the ball valve because of the inline easy open/close but that is another whole system to fuss with and a bit more complex than the on off from the above system€¦

Hmmmmm


What are the normal ram sizes in your HW€™s? We were thinking in the ball park of 6€x8€-ish€¦ What is this Woody valve you speak of? We are trying to get a CNC shop to do some work for us so if might not be out of the realm of possibility.

[woody]

FP HW Tips

Cheers Mario ...
Working out the opening time for the ball valve will require finding the load or torque to open it.
A value picked off the net suggests 110 lbf-ins for a 1 ball valve.

Throwing some values in the calculators gives me a loaded opening time of around .09 second ( when using the afore mentioned 1 bore 3 stroke ram @ 150 psi )....increasing the bore to 1.25 gives us some extra OOoomph and reduces the calc opening time to 0.066 second with a required Cv of around 0.5.

Standard disclaimer ...
IF Ive got my calculations correct etc ..

[woody]

FP HW Tips

A F.P. 3 port valve made by me sometime ago...

http://www.robowars.org/forum/album_pic.php?pic_id=1422http://www.robowars.org/forum/album_pic.php?pic_id=1422

http://www.robowars.org/forum/album_pic.php?pic_id=1420http://www.robowars.org/forum/album_pic.php?pic_id=1420

Currently residing in my Feather