Modified offset dies

Maybe a cheaper route to a corrugating die set can be had by modifying one of an press brake offset die pair?


Press brake offset dies (YouTube)
Video shows a press brake offset die pair being used to create an offset, joggle or narrow return bend in a sheet of metal.

The offset dies are not suitable for corrugating as they are off the shelf because if you try to make an offset bend pair too close to a previous offset bend pair the previous bends foul the tool.

Maybe though a simple modification by grinding or machining one of the offset dies would allow offset bends to be placed right next to each other, forming corrugations?

The Italian firm "Rolleri" have a catalogue of press brake dies and their range of offset dies is in handy 0.5 mm increment sizes of interest.



So selecting their 5.5 mm "CEZ 5,5" offset die as an example to plan a modification for, here could be the grinding or machining modification required for corrugating.



The basic idea is shown in this diagram with

• the yellow colour indicating the position of the sheet and raised position of the standard offset die top tool before the press action, and
  [/*:m:24ewjkip]
• the purple colour indicating the new bend on the sheet and the position of the top tool when the press brake presses it down.[/*:m:24ewjkip]

If modifying the Rolleri offset tools there would be a further problem with the descending sheet at 45 degrees not clearing bottom tool holder.



I suggest that this problem might be solved by soldering, brazing or welding a base to the bottom modified offset tool as shown here.



For wider sheets that I would like to have made, the fact that the sheet descends at 45 degrees at both the front and the back of the press brake could cause a problem of the sheet fouling some press brake's back-gauge, though perhaps that could be overcome by removing the back-gauge?

One other possibility might be to swap the top and bottom offset dies around and have the 45 degrees going upwards, though this would require a more difficult task to position the sheet for bending.

 

Re: Modified offset dies

Yes on second thoughts, it looks a much better solution with the modified offset die as the top die.



The yellow line indicates the positioning of the sheet against a back-gauge for a down-stroking press brake, before the press action.

The green line indicates the positioning of the sheet against a back-gauge for an up-stroking press brake, before the press action.



Here instead of adding a base to the modified die, the red area indicates the edge of the top die holder which must be machined off to stop fouling the sheet at a 45 degree up angle.

Here note the edge of the die labelled "L" is at a sloping angle to the vertical. The reason for this is to provide a positioning stop for the sheet (as an alternative or additional stop to the use of a back-gauge stop) to allow space between the corner of the previous bend in the sheet and the edge of the die, to allow for the sheet being pulled in by the bend. The "L" angle shown is for illustrative purposes only. I have not worked out what the angle should be for best results yet.

 

Re: Modified offset dies

OK, this is what I have now.



Here's a tidier wide-angle diagram.

 

Versatile corrugating tool

The press brake double V-die tool, the Amada 12206, can be custom modified by grinding to allow the tool to "revisit" previously formed corrugations to allow the bends to be selectively increased to curve or straighten panels.

With the standard V-die, you get one chance to get the bend right because you can't go back and re-do a bend. This modified versatile V-die solves that issue I think.







Amada quoted £226 or $350 extra for the modification in addition to the £127 or $200 for the cost of the standard tool.

 

You might find what you're after from here:

http://www.cadischmda.com

 

I am familiar with that website and Cadisch MDA and have previously contacted them for a price for wave-profile cladding sheets from the MN WellTEC range which they are UK distributors for (and is the same range sold by Rigidal).

It is up to the manufacturer MN to set the price for sheets which they charge Cadisch MDA and this price is too high. Unless and until MN slash their prices for a small number of sheets and stop adding on a prohibitively expensive "set up charge" then their prices at £600 or more for one sheet of area of less than 2 metre squared is too high for me.

 

Corrugating barrel or drum rollers

I don't mind you asking at all. That does not mean that I can detail my plans here. In outline I have a few ideas for my own home DIY projects. I am not very far advanced at the project planning stage so have nothing much to report at this stage. I'd prefer to show people after I have completed a project. Also I don't want to count my home DIY project chickens before I have sourced my wave-profiled cladding sheets eggs. I don't want to digress into project design idea specifics because I don't want to be thought to be inviting alternative suggestions as regards alternative materials, different methods etc. I want to stay on topic and so avoiding "what's it all for" questions and answers is best I think and I hope you don't mind me leaving it at that.

Thanks. It is nice to be appreciated on the merits of my posts. Curiously, on some other forums the equivalent topic I started has been locked or even deleted! Particularly this seems to be the case on blue-collar metal working or craft forums where some of the skilled worker forum members perhaps see me as a "condescending white collar" scientist and engineer type (someone they don't quite understand but they are sure they don't like me) who is not welcome to turn up to their forum and dare to post my own many alternative ideas. Sometimes a few hostile individuals on such forums have googled my name to find out my employment status, politics and dating preferences and have then posted such off-topic irrelevances about me, to attack the man rather than his ideas, "ad hominem" attacks, and so questioned the value of the topic, even questioned my own sanity - all with a petty aim to troll, derail and sabotage the thread. Such poor quality posts in a topic can give the wrong impression of a doomed topic to the forum administrator. Instead of surrendering to such trolling, the forum administrator should have deleted the poor quality trolling posts but some administrators don't like to side with the forum newbie (me) against the forum regulars, so that is why those other forum administrators in those other forums have locked or deleted the topic, I guess? I presume forum administrators who seek to maximise advertising revenue would rather have more unoriginal unpleasant trolling members frequenting their forum than fewer thinkers with original ideas?

Thankfully, we don't seem to have that problem in this forum but hopefully if the trolls turn up here you as forum administrator will recognise their malign intent and deal with them accordingly.

Hey no problem Gareth. Here is another idea worth consideration.

I have produced this animated gif file with 4 frames, so give your computer time to download all 4 frames before expecting to see the animation.



The animation is supposed to be a cross sectional diagram of corrugating barrel or drum rollers, which could have "V" grooves machined along the length.

This is much the same idea as the jeweller's Zig-zag machine already posted above



but such corrugating rollers could be made on a bigger scale, perhaps adapting a slip roll machine?



For example, someone wishing to build a model aircraft made corrugating rollers as seen here.




These were to corrugate thin aluminium sheet to round-profile corrugations so steel rod soldered onto the rollers was sufficient for this job but the corrugations were about the right pitch or wavelength so the method is of interest.

To bend steel sheet of thickness of around 1.0 mm stainless steel, the weight of the rollers increases rapidly in order to keep the required stiffness to weights that need a crane to move the rollers alone as the length of the corrugations increases.

For example a 3m length of 130mm diameter steel round bar would weigh 312 Kg, for 120 mm diameter, 3m weighs 264 Kg!

The rollers needed to corrugate only half that length or 1.5 m are much more manageable in weight terms.

For this shorter length steel round bar of perhaps 80mm diameter would be stiff enough which weighs 39.5 Kg /m which at 1500 mm would weigh 59.25 Kg per roller which is a much more practical weight to consider for a home DIY machine.

Selecting 85mm (3.35") diameter weighs 44.5 Kg/m at 1500mm would weigh 66.75 Kg per roller.

 

I've found a video of a press brake fitted with a corrugation die set.