The shape of the corrugations profile is drawn here
 

The nominal thickness of the sheet (T) should be selected between 0.8 mm and 1.0 mm
 
The desired dimensions of the profile can be calculated from the sheet's nominal thickness (T), from these simple "in proportion" equations.
 
The bend separation width along the sheet is (B) is 5.5 x T.
The amplitude (A) is 4 x T. This is also the overall thickness of the panel.
The wavelength (W) is 8.4 x T.
The angle of the bends is 90 degrees.
 
To give a few examples.
 
If sheet of thickness 0.8 mm is selected then these dimensions would be desired
B = 4.4 mm,  A = 3.2 mm,  W = 6.7 mm,  S = 4.8 mm
 
If sheet of thickness 0.9 mm is selected then these dimensions would be desired
B = 4.9 mm,  A = 3.6 mm,  W = 7.6 mm,  S = 5.4 mm
 
If sheet of thickness 1.0 mm is selected then these dimensions would be desired
B = 5.5 mm,  A = 4.0 mm,  W = 8.4 mm,  S = 6.0 mm
 
Tolerances
 
I don't know what tolerances to expect from a press brake. I can suggest the sort of tolerances I feel I would be happy with and ask if this is a reasonable expectation?

If I have to relax my tolerance expectations to keep within my budget then that is what I will do to get my panels sourced. I am not holding out for the impossible.

Suggested tolerances

A = 4 x T ( +/- 0.25 mm ) – Amplitude equals four times the nominal thickness
W = 8.4 x T ( +/- 0.5 mm ) – Wavelength equals eight point four times the nominal thickness

That is saying for A, the sort of tolerance might be plus or minus 0.25 millimetres.
For W, the sort of tolerance might be plus or minus 0.5 millimetres.

B = 5.5 x T ( +/- 0.25 mm )

In general I am more forgiving of bends which are too close together rather than too far apart. In other words on B + 0.2 mm but - 0.5 mm might be more like it.

That is suggesting for B a one-part tolerance of plus or minus 0.25 millimetres, but then suggesting an alternative two-part tolerance of plus 0.2 mm and minus 0.5 mm.

Perhaps I'm complicating matters stating two tolerances for the one value but the press brake operator might like to know that the same plus or minus tolerance is not as descriptive of my tolerance as a different plus and minus tolerance.

I should also say that I am looking for about 90 degree bends which means I have a tolerance I suppose on the ratio of W/A (Wavelength divided by amplitude) which should equal 2.1 and lets say +/- 0.1 for tolerance on W/A as a starting point. (There are no units such as mm on the tolerance for W/A because it is a tolerance on a ratio – W divided by A – and ratios don't have units.)

In other words I don't want A to be -0.25 mm at the same time that W is +0.5 mm because that would make W/A something well over 2.2 and too flat a profile, nor do I want the reverse and too sharp a profile.

On the other hand if A and W go up or down together because of variations in B, the bend separation width then that is less of a problem because W/A and the angle of bend will stay fairly constant.
 
Other method – Sheet metal brake folder
 
I am just looking for the options to fabricate my panels at low cost.
 
Although I explain below how to make this profile using a press brake it is possible that a sheet metal brake folder, or a box and pan folder or cornice brake, might be used instead if it had a particularly narrow thickness of folding bar where it presses against the sheet.
 

Normally for sheet metal brakes the thinnest folding bars are about 1/4", which I think is a little too thick. Some sheet metal brakes allow for the use of an "Insert bar" for minimal reverse bends, and if a especially thin insert bar was made and fitted then it might work OK.
 
This profile can certainly be made using a press brake from flat stainless steel sheet (this is how the sample was made I believe) by making bends using some 6 mm V-dies as shown in the diagrams. The sheet has to be manually turned over before each fold.
 
Press brake V-dies.
 
The 1.0 mm thick sheet (100%) profile would be produced by a standard 6mm V-die.
The 0.9 mm thick sheet (90%) profile might be produced by a standard 5mm V-die or a modified 6mm V-die.
The 0.8 mm thick sheet (80%) profile might be produced by a modified 5mm V-die.
 
Press brake method – example 1.0 mm sheet thickness profile
 
If sheet of thickness 1.0 mm is selected then these dimensions would be desired
B = 5.5 mm,  A = 4.0 mm,  W = 8.4 mm,  S = 6.0 mm
 
This image shows the position of the sheet relative to the 6mm V-die block before the 3rd bend is made. The top tool is not drawn in.
 
In these diagrams, the front of the press brake is to the left, the back to the right.

There would seem to be two alternative possible ways to position the sheet for each fold
 
If a CNC press brake is used, the back edge of the sheet could be positioned against the back-gauge which would move under operator sequenced CNC control by a set distance before each fold.

Or, and this would seem to be the only method for a non-CNC press brake, a strip of steel could be attached (either using a strong epoxy glue such as Araldite, or soldered) along the vertical side of die block which would serve as a shim between the die block and the vertical side of the previous bend and the sheet could be positioned against the shim on the die block.
 
Each proposed method of manufacture has its own advantages and disadvantages no doubt.
 
This diagram shows the position of the sheet after the 3rd bend is made. Again the top tool is not drawn. 
 
Not all die blocks with a 6mm V are suitable for this job. The 6mm V does have to be quite close to the edge of the die-block. Fortunately, this is the case with some of the Double V Dies, of the type to fit an Amada press brake. 
 
There are a few similar Double V-dies listed in the Amada catalogue and possibly this one is the best one for this job if I have to buy the dies especially for this work.
 
 
 
2 of those 123061 bottom tools would cost £254 which would give me panel length folding of up to 1670 mm.
 
3 of those 123061 bottom tools would cost £381 which would give me panel length folding of up to 2505 mm.
 
Press brake method – example 0.9 mm sheet thickness profile
 
If sheet of thickness 0.9 mm is selected then these dimensions would be desired
B = 4.9 mm,  A = 3.6 mm,  W = 7.6 mm,  S = 5.4 mm
 
One method is to modify the standard 6mm V-die by custom grinding one edge of the die as follows -

This then would allow a closer bend as follows -   

In this diagram, I am assuming a CNC backgauge stop is being used because I have left a 0.2 mm or thereabouts gap between the vertical side of the sheet and the die. 

A very slight change to those diagrams would suit a plan to use the die itself as a stop.

One idea is simply to use the side of the die as a stop expecting this to produce a 0.2 mm shorter bend separation width compared to the 90% profile  

Using the die as a stop might mean a slightly smaller profile with wavelength dimension of about 7.4 to 7.5 mm and an amplitude of 3.4 to 3.5 mm. If this works out it may well be acceptable as a profile to aim for .

Press brake method – example 0.8 mm sheet thickness profile
 
If sheet of thickness 0.8 mm is selected then these dimensions would be desired
B = 4.4 mm,  A = 3.2 mm,  W = 6.7 mm,  S = 4.8 mm
 
If sheet thicknesses less then 0.9 mm are selected, such as 0.8 mm then a smaller die would need to be used, such as a 5mm V-die, which may need a custom grind as well.
 
This is a diagram of a 5 mm V-die is straight from the Amada press-brake die catalogue.

Alternative makes of similar tools might be slightly cheaper to buy, or it might be possible even to hire out those dies and suitable punch tools for this job?
 
Not every company with a press brake will have the correct V-dies and punches to do this job in house to begin with so we may need to look at the options to buy or hire the right tooling to do the job.
 
This extract from the Amada reference pdf recommends tonnage of 17 per metre and to bend to an inner bending radius of 1mm.
 
 

View Chart image full size

 
The appropriate punch or top tool to use we can discuss later but I think many punches would work well enough providing they are 88 degrees or less with a point of 1mm radius or less.
 
As you can gather I hope, I have researched this method of manufacture in some detail so I believe these panels can certainly be manufactured this way.
 
Possibly there are other methods, perhaps using different tools which would be worth considering so if you can think of another (cheap) way to make this panel please feel free to make suggestions for alternative manufacturing methods to me.
 
Mass production of similar architectural facade panels uses roll-forming most often but this is not practical or affordable for a custom design of panel.

Panels size
 
Also there is the question of exactly how big the panels can be made? There is no set size demanded, but I would prefer bigger panels all other matters being equal. Bigger panels are more difficult to make well so there will be an upper limit to the size of panel which can be made which may well be less than the size of the steel sheet as supplied.
 
The total area of sheets to be bent is likely to be enough to make about 10 metres squared of panel from 316 grade stainless steel in total – possibly less if the expense of manufacturing each panel is more than I hope.

Number of bends
 
The total number of bends required varies even with the same area of sheet to be bent into panels depending on the length of the bends. The longer the bend, the less bends you need to bend the same area of sheet.
 
bend separation width = 5.5 x thickness
 
100% profile thickness = 1.0 mm, bend separation width = 5.50 mm
 90% profile thickness = 0.9 mm, bend separation width = 4.95 mm
 80% profile thickness = 0.8 mm, bend separation width = 4.40 mm
 
This bend separation width would presumably also be the incremental movement of the CNC back-gauge between bends.
 
 
Consider 2 options of starting size of sheet to cut to size to make panels.
 
The supplied sheets are first cut to a size suitable for bending and which are light enough to be flipped by one press brake operator.
 
For a 0.9 mm thick sheet these pieces of sheet weigh 7.5 Kg or 16.5 lbs each.
 
Option A.
 
4 sheets supplied at 2500 mm x 1250 mm – total area of sheet 12.5 m2
 
Cut each sheet in 3 – 2 cuts per sheet, 8 cuts total
Cut into 12 sheets each at 2500 mm x 416 mm
 
Total width to be folded 5000 mm
 
Number of bends
1.0 mm thickness -  909 bends
0.9 mm thickness – 1010 bends
0.8 mm thickness – 1136 bends
 
 
Option B.
 
6 sheets supplied at 2000 mm x 1000 mm – total area of sheet 12 m2
 
Cut each sheet in 2 – 1 cut per sheet, 6 cuts total
Cut into 12 sheets each at 2000 mm x 500 mm
 
Total width to be folded 6000 mm
 
Number of bends
1.0 mm thickness – 1091 bends
0.9 mm thickness – 1212 bends
0.8 mm thickness – 1364 bends
 
So although the area of sheet in option A (12.5 m2) is slightly greater than the area of sheet in option B (12 m2), nevertheless the number of bends required in option A is less, because the bends are longer in option A (2500 mm) than the bends in option B (2000 mm).
 
 
So my question is how much would it cost to get the corrugated panels manufactured? Perhaps you would like to quote now or later for this work?
 
Thank you for your interest in my project.
 
Yours sincerely,
 
Peter Dow
Aberdeen

GarethBell said:

Welcome to the site.. Where did you get the example from?

Hi Gareth and thanks for the welcome!

Where did I get the sample whose photograph I posted?

It was made by a precision sheet metal company in England whom I will not name but if they want to step forward and claim credit for their sample they are invited to do so.

The sample was well made and provided for free so I had no complaints about the company themselves, they did their best as a first effort and well done to them.

However, although the sample was good it was not quite right and within specification. The drawing we had agreed specified a nominal thickness of sheet of 1.0 mm but they had selected a nominal thickness sheet of 0.9 mm to use and the company claimed, rightly I believe, that nominal 1.0 mm thick sheet was not so easy to source and more expensive.

I asked if they would try again to provide a 1.0 mm thick sheet sample but the company asked hundreds of pounds paid up front by me to them before attempting to provide another sample within specification.

Although I am happy to pay for any samples received within specification upon receipt of a sample within specification, I am not happy to pay money beforehand where no samples with specification have yet been produced. I want to know that a company can produce this within specification before paying them money "pro forma" which might go to waste.

At the time of getting that sample made, I had not specified a profile for nominal thicknesses other than 1.0 mm so I did not say the following to that company though saying the following to them at that time or even now would make no difference because it was their demand for cash up front which was what stalled further business between us.

Since the problem of sourcing 1.0 mm has come to light and considering anyway that a thinner sheet would work well but only if the profile was scaled down to suit, I have specified profiles which are scaled down in proportion for the range of nominal thicknesses from 0.8 mm to 1.0 mm.

So with this new specification which allows for a range of thicknesses there is no problem per se with using 0.9 mm thick sheet but in this case all dimensions require to be scaled to 90% of the 100% values used for the 1.0 mm thick sheet profile.

GarethBell said:

Sounds like they aren't great with customer service…

A quick google search

Yet out of hundreds of companies I have contacted for quotes, involving many weeks of google searching on and off, that company was the best so far because at least they provided a free sample that was within 10% to 15% of specification and their sample makes an excellent photograph to illustrate the profile I am after for future requests for quotes.

Perhaps they did not appreciate because they never asked and perhaps because I didn't spell it out at the time, assuming they would just use 1.0 mm thick sheet, but my tolerance for this project turns out to be more like 5% or 6% and so starting from 0.9 mm was doomed for attempting to meet the then agreed drawing which assumed 1.0 mm thick sheet.

Their subsequent policy of requiring payment up front before doing fabrication work, even small samples, is typical for the industry I am finding. Typically the few companies who will quote require "pro forma" contracts and I hit this "Cash up front! " brick wall before they will even provide a sample.

GarethBell said:

A quick google search got me to this site.. http://www.samsfabrications.co.uk/

They say "If you can draw it, we can make it"

I did contact that company last year-

SAMS Fabrications wrote:

Dear Peter,

Thank you for your enquiry. Unfortunately it is with regret that this is not our type of work.

Declining to quote is the most likely reply but no reply at all is even more popular. I am finding it very hard to get quotes at all.

GarethBell said:

What are these sheets for?

My home DIY. This style of sheet is referred to by architects as "cladding sheets" and most often you see them on a visible surface such as a wall, either exterior or interior. A wide range of such sheets can be purchased from a German company called  

"MN Metallverarbeitung Neustadt GmbH" but I just call them "MN".

They offer a huge range of different profiles for architectural cladding sheets.

Download PDF of their catalogue – Right-click save target as …

The nearest to my desired profile is their wellTEC W-4/10 with a wavelength of 10 mm and an amplitude of 4 mm. It is not the profile I want but if it was cheap enough I would probably buy it and make do.

The MN panels are pricey, certainly in small quantities – for one sheet of less than 2 metres squared they quoted me £600 – maybe 3 or 4 times the cost of the flat sheets of stainless steel they are made from. Their quote is so much their sales person claimed because of "set up costs".

I reckon that MN don't have a competitor in this market who offers such a wide range of profiles so they can charge more or less what they like for their unique profiles.

I think I would need 5 or 6 of those sheets for my home DIY concept and I am thinking this would cost me too much to buy from MN.

I guessed there might be a cheaper way to custom make my panels and although I am making progress in terms of "how" I have not yet got a quote to deliver within my budget.

As I am making the effort to design my own custom panels and to find someone to make them then I do expect my design to be manufactured within reasonable tolerances.

Alexander m said:

Why must the sheets be made to such a high degree of accuracy and also why won't just any size of corrugated sheet? You say it's for the outside cladding of a house and if thats the case then why won't aluminum siding suffice. Its sounds more like your making heat shielding for the space shuttle.   

Since we have got on to aerospace, this is what someone from a company who does work in that area replied to my request for quote.

Good morning Peter,

I am surprised by your experiences with sheet metal fabricators, perhaps this is why British Engineering is on the downturn. The form you require is a standard exercise for our apprentices. It utilizes many features of the brake press and encourages the use of extra features such as side stop guides to keep the folds parallel and square.

I do understand perhaps some reluctance from the bigger companies such as ourselves as our core arena is Aerospace and with respect this order would be too small for us.

…

The size of the panel mentioned factored more than just weight. The throat of a brake press will not take 2M so the sheet you propose would have to be orientated laterally but this means a 2M fold.

As a single fold this is ok but due the high proportion of folds very close together , keeping them parallel will be an issue. If these are decorative then the Human eye is very adept at spotting this type of discrepancy.

This then means more time on the job and increased cost. Smaller panels are easier to manufacture and therefore quicker so it does not necessarily follow that less panels is cheaper.

So that answers the accuracy point.

The size of corrugations is by design. Why doesn't all wallpaper have the same design? Why should metal walls have the same design then? Do you want to live in a house where everything is the same as another house? I don't. DIY gives you a chance to put something creative of your own in sight. Is that wrong?

I said what I said – "exterior or interior". Interior does not mean the outside, it means the inside.

In Aberdeen, the houses are often made from granite stone and so we don't need aluminium siding on the outside of wooden-walled houses.

Stainless steel is stronger for security and has better resistance to heat than aluminium, though the heat danger in my home would be from fire, not from re-entry from orbit!

Look I understand your curiosity folks but I am not looking for second guesses as to my project design but quotes to turn my project design into panels.

Nor I am looking for suggestions that dissimilar panels should do but quotes to supply any panels from off the shelf which are similar.

andrewk said:

Here in the States, we have made something similar at the machine/ sheet metal shop (aerospace MRO) I work in, the customer was billed well over $2000 to bend smaller pieces that had to be less accurate out of aluminum. Sadly, we do not do outside work, and I cannot see a shop here being any less expensive than that, before shipping. However, I will try asking around (it would probably be .032" sheet, roughly .8mm).

Thanks. I wrote an interesting reply but it timed out and I lost my post. No time to re-do.