[thefu]

Im looking to purchase a press brake to keep business in the shop. Ive found an inexpensive mechanical press brake.

I only have experience in hydraulic so far and the question I have is. Can i control the stroke or bend depth on a mechanical? Im using 4 bend lines to create an aprox 19" radius in a flat steel plate. The shop i have do this now has doubled their price and its not worth it for me to purchase a press brake.

[Al_The_Man]

The most basic method would be to use a linear scale on the ram and a small controller such as a PLC with encoder capability input and control the hydraulic valve when depth is reached, a 2 or 3 line data input unit could be used for operator input.
It sounds like the operation really needs a Rolling machine?
Al.

[thefu]

the problem is the force requires for rolling AR500 (which is really hard metal, 470-530 brinell hardness)

most large powerful rolling machines are just too large to roll it. the plates are 10"x12" and need the bends running longways so you only have 10" to play with.

its my understanding that mechanical press brakes dont use hydraulic's. that being said how would i control the stroke?

[Al_The_Man]

Oops, I overlooked that.
In light of that it will be a bit of a problem as most mechanical engage a clutch and do one complete revolution, IOW you cannot do part of a rev.
IIRC, you can only set for one depth at a time by setting die height? Is this a problem with this kind of job?
Al.

[thefu]

i suppose setting die height would be the way to do it, I dont have much press brake experience and i have zero experience with mechanical.

So its 1 full rev or cycle of the ram per engagement of the clutch.

is there a common easy way to set the die height?

[Al_The_Man]

So its 1 full rev or cycle of the ram per engagement of the clutch.

is there a common easy way to set the die height?

I have had very little to do with mechanical, most of the work I do is fitting height and back gauge control, so these would be Hyd.
Maybe someone with Mech brake experience will jump in?
Al.

[thefu]

its such a simple job idk why my current place wants to charge $13 to bend each plate...just absurd i think. I found a 60 ton mechanical for $4500 here locally plus $650 to rig it to my shop. I have a cnc mill in the shop so i technically could make the dies i need if i cant find them cheap

[gridley51]

Mechanical pressbrakes are usually fixed stroke.The depth of bend is controlled by raising/lowering the top or bottom beam.
This will do your job fine if the four bends you do are all the same.If they are different it will be a PIA constantly having to adjust the machine.
It will also take you a couple of tries to get the position right but will get easier with practice.
We used to have mechanical pressbrakes but they are all hydraulic now.
Some people do what you want to do with ordinary vee tooling,others with bullnose tooling.It depends on the finish you need.
We make full radius punches and dies for each product.

[thefu]

All the bends are the same, thankfully. Might take a few plates to get right as you said but i think i could make it work easily.

my quoted price was just doubled minus $1. they are trying to charge me roughly $10 per plate to form..i think thats way too much for something thats not precision by any means.

I planned on purchasing 1024 pieces that were formed and with the added price, it would cost me an additional $10240!! all for 2 days of work i could do myself or hire someone with my machine...

some shops just seem to be getting more and more greedy.

[kevin swan]

That sounds like a nice job for ether type press . I think the key to the job would back gaging the 4 bends so that you are not re handling the plates

[malzeri83]

Absolutely sure than on hydraulic press brake with numerical control the stroke is controlled (means the final position of stop of punch)