Why is this job so difficult to quote for?
Fabrication of stainless steel corrugated panels
I am enquiring to see if you will tender a quote to do this job or if not yourselves perhaps you can recommend a company for this?
I'd like to find a manufacturer to bend stainless steel sheets to make some corrugated panels of a custom design of my own, which would be similar but bigger than this small sample.
The shape of the corrugations profile is
This profile can be made using a press brake from flat stainless steel sheet 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.
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.
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.
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.
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.
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.
Other minor issues to watch out for would be making sure to find a steel supplier who will supply genuine 1.0 mm thick stainless steel sheet, and not the common 0.9 mm thick substitute.
The total area of sheets to be bent is likely to be about 10 metres squared of 316 grade in total - possibly less if the expense of manufacturing each panel is more than I hope.
I can certainly afford the sheet steel, the 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.
Last edited by Peter Dow; 01-14-2011 at 10:06 AM. Reason: To edit title
Why is this job so difficult to quote for?
We'd be interested in quoting this for you. Our press brake is 8ft (96" long), 75 ton hyd. CNC. You are correct that this is possible, I have done similar bending for another customer that is using perforated sheets, it is a grill for tractors. Will 8ft long pcs work for you?
I am thinking initially that the shipping cost to ship the finished panels from the USA to Scotland would add a lot to the cost. Would it?
I was thinking that a company in Britain or maybe Ireland would save on delivery costs.
I presume you noticed I was in Scotland and that explains why all my measurements are in millimetres?
Sure 8ft long panels would be fine; the gross size of the panels is not critical. 8ft, 7ft, 6ft - is all fine.
What is more important is the size and profile of the bends which depends on using the right size of V-die for the desired profile.
For the size and profile shown in my diagrams, a 6mm wide V-die is needed. Well you can see that size in the photo.
Since posting the diagrams I have been thinking it would be nice to get quotes for a slightly smaller profile, in slightly thinner sheet steel, as well which would use a 5mm wide V-die to make corrugated panels out of say 0.8mm thick sheet.
I don't have a photo of the smaller size because I don't have a sample of the smaller size. I can produce diagrams of the smaller size in due course but since the diagrams and photos shown are about the desired size, I trust a quote for one size would be about the same as a quote for a slightly smaller size?
Do you have or could get such small V-dies and with the V-die close to the edge of the block as well as would be needed? What size of blocks do you have that you'd plan to use? Any references to the catalogue model numbers of the tools you plan to use would show me what tooling you have in mind for this.
I had a company in England confidently saying they could produce this but when I got their sample, it turned out it was made using a bigger V-die, say about 8mm wide and the bends were just not small enough for my needs.
Last edited by Peter Dow; 03-17-2011 at 10:29 PM.
Are you seeing that photo OK? Sometimes imageshack who host the images refuse to serve it and all you see is a picture of a frog. If that is a problem I think this forum allows me to attach images, and I have attached some images to this post.
If you can view the drawings in my first post, they give a more detailed description of the desired profile.
If you can imagine a much bigger panel, about 10 times wider and say 30 times longer than the sample shown in the photo, but with the same or even better a slightly smaller profile, so it would be like hundreds of those small samples stuck seamlessly together to make a big panel, as big or bigger than the size of a doorway, and enough of those panels to cover a total area of 10 square metres ( 107 square feet).
Delivery from China sounds as or even more expensive than delivery from the USA. Production costs can be cheaper in China for a larger order but I am not sure whether it works out cheaper from China for a small order for one guy's DIY?
Last edited by Peter Dow; 03-18-2011 at 08:40 AM.
Yep....shipping costs would be steep. If I had to guess, probably about as much as the material and labor combined.
I might have another idea for you. The grilles that I bent before were done with a deep-v punch/die. The sizes you're talking about are fairly small though....could be an issue. However if you were to machine a male/female set of you're profile into a 2"x2" or bigger chunk of steel and put a keyway on them. You should be able to stamp these at any profile size. Alot of machining.....but definately possible. Would also take a press with a good amount of tonnage to turn an 8' blank.
Hope that helps ya,
or see the attached image.
I would think it will save on costs if someone has these or similar tools in house already.
Much bigger V-dies or V-dies which are not close to an edge, like the V-dies on the double V-die tools are close to the edge, are not suitable.
There could be other off the shelf tools which can do this. What I need at this stage is for someone who reckons they have suitable tooling available to show me pictures and or diagrams of their tools, so I can see if I think their tooling is suitable.
You might need to produce these with a rolling die.
Like I said in my original post.
This video shows a roll forming line for large size corrugated steel sheeting often used for roofing etc.
[nomedia="http://www.youtube.com/watch?v=tQYic4PQX-M"]YouTube - Corrugated Steel Panel Roll Forming Machine[/nomedia]
Roll forming therefore requires a large capital investment of maybe tens of thousands of pounds (or dollars) in tooling which is suitable only for rapid mass production with minimal labour costs, not for a small custom order totalling 10 square metres or 107 square feet of product.
Having said that there is a German company by the name of "MN Metallverarbeitung Neustadt GmbH" who do offer such a wide-range of corrugated profiles, for example -
Sinusoidal profiles -
Designbleche, Metallverarbeitung, Coilcenter - von MN Metall
Designbleche, Metallverarbeitung, Coilcenter - von MN Metall
that I do wonder how they manage to have a different set of roller dies for each profile? It could be that MN is such a large company with many customers that they can afford a huge investment in tooling?
Although MN offer a wide range of profiles, they don't have a profile exactly as I would like - their small sinusoidal profiles are too flat and their zig-zag profiles are all too large.
The nearest profile they offer I might be interested in, their agents in England were charging about £600 to £700 or $970 to $1100 per sheet 1.5 metres x 1.2 metres or 5 feet x 4 feet.
In other words, they are charging more for one sheet than the cost of a set of press-brake dies. So I figure there has got to be a cheaper way - and get the profile I want - by looking for someone to quote to produce my custom profile using a press brake.
Or maybe you had in mind something different and much cheaper when you mentioned "a rolling die"? I have not seen any possibilities of "a" cheaply available "rolling die" which would do this job but if you would like to explain further I am interested to know what you meant?
Last edited by Peter Dow; 03-22-2011 at 12:05 AM.
ATTENTION PRESS BRAKE OPERATORS - Please read my REQUEST FOR QUOTE!
I have drawn up a few diagrams showing the appropriate way I believe to produce small-corrugations, "wave profile" panels using a press brake from steel sheet of thickness 0.9 mm, which would I think give a wavelength of about 7.6 mm and an amplitude of about 3.6 mm.
To make this profile using a press brake, a standard #12306 Amada 6 mm V-die or equivalent needs first to be custom ground to suit.
The next diagram shows the position of the sheet after two bends have been made and before the 3rd bend is made -
The above diagram assumes 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.
The next diagram shows the position of the sheet after the top tool (not drawn) has been pressed down onto the sheet to make the third bend.
One slight variation on these drawings is simply to use the side of the die as a stop (no CNC back-gauge required) which presumably would produce a 0.2 mm shorter bend separation width than as shown.
Using the die as a stop might mean a wavelength dimension of about 7.4 to 7.5 mm and an amplitude of 3.4 to 3.5 mm.
REQUEST FOR QUOTE
So whether using a CNC back-gauge stop or the die as a stop, will anyone, especially in the UK but I'll consider quotes from elsewhere, with a press brake please now step forward and quote to make 12 panels by bending 12 sheets of stainless steel, grade 316, 0.9 mm thick, sheet size 2 m x 0.5 m, which involves making about 101 bends (using the CNC backgauge stop method and a bend separation width of about 4.95mm) to 105 bends (using the die stop method and a bend separation width of about 4.75 mm) per sheet, to this profile? The bends would be along the longer length of the sheet - 2m long bends in a 2 m x 0.5 m sheet.
Either that or quote me for what you and your press brake could make something like this plan please.
Here is a new diagram I have drawn to show the range of profile sizes I am interested in.
1 millimetre = 0.0394 inch
5 millimetres = 0.197 inch
Hi, it might be helpful to know what your minimum size sheet is. The reason I mention it, is that maybe a sheet metal place could stamp the pattern into it in one shot. It will stretch some areas a bit thinner than others, but maybe that is ok.
It might seem odd, but for a low volume like this, it might make sense to just machine it from a block. When milling side 1, it can lay flat. For side 2, it can sit on a jig to support the waves on the bottom.
This would allow making any variation of sizes and shapes that you want.
The chips will be recyled, so don't worry about that.
Imagine that you are being asked to produce a large repeating pattern by hand. One mistake (or slight variation in the pattern) will show up to the eye very intensely. 50 years ago there were a lot of craftsman in the business, but even they made mistakes. (scrap) People today are still craftsman, but with different tools - CNC. It was invented to reduce the fatigue of such jobs. IMHO, that is why people are not really bidding.
You did get at least one interested supplier - yes, shipping can be expensive. That is the nature of the world. I have a supplier in Australia for some certain work, and they are a gem. Trust me, I didn't make that decision lightly, and paying them often cost more in fees than their work.