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Thread: Numbers on sheetmetal surfaces

  1. #1
    Project Engineer CCR5600Design's Avatar
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    Numbers on sheetmetal surfaces

    Folks,

    We have a request from one of our customers to permanently mark the mounting rails used in a data cabinet for the purpose of identifiying individual RU (rack unit) positions within the cabinet. They would like to see a stamped number in the rail for each position in both the LH and RH mounting rails. We do not have the tooling in house necessary to punch the numbers into these rails, so I started checking with our vendors to see if they had a solution to this request. Every single one of them responded they were unable to efficiently mark the surface of the rail, citing tooling costs and excessive punch time.

    Are any of you familiar with a way to quickly etch/stamp/emboss numbers and letters into sheetmetal? I really don't want to drive the cost of this cabinet through the roof, so anything that would be cost effective would be welcome.

    We are also considering screenprinting the rails after painting them as an option.


    Thanks,


    Ron

  2. #2
    Administrator Kelly Bramble's Avatar
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    Stamping and embossing will require tool modification or a new tool (Separate process or step). I would take a look at laser marking and ask how youR customer feels about a peel and stick label...

  3. #3
    Senior Engineer Marky's Avatar
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    Hi Ron Take a look at Electo-Chem Etching http://www.ecemmi.com/. I was going to use it on our products but convinced them to buy an engraver. I have a Dot-Peening Engraver that has worked very well for us.

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    Lots of options Ron,

    I would first advise against the screen printing as it is not really permanent with knocks and scrapes making "8" look like "3" etc.

    My first choice would be laser marking. Look for someone with an Nd-Yag laser as CO2 engravers will not mark metal. Although having said that, there is a compound that a CO2 laser can burn to make a quite permanent mark on metal. It is not a cheap compound, but a simple process providing the CO2 laser has enough power, 50+ Watts.

    You could try using tags pop-riveted to the shelf. There are zillions of tag manufacturers providing the gamut from hand written aluminum to embossed letters.

    Another tag-type could be anodized aluminum and they can be laser marked with a CO2 (which I have {grin}) It is a permanent mark as it boils off the color and leaves a white mark behind. Sample I burned into a pocket knife.

    Also, you may want to check stuff like this...
    http://www.summitsignsafety.com/stor...D=7E5242424F19
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  5. #5
    Lead Engineer RWOLFEJR's Avatar
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    Any chance of incorporating a stamp in the processing of the rails? Example... We place stamps in our clamp blocks for a forming operation here. Maybe a break could have the letters or numbers standing proud of the break via an insert and impart your digits during normal operations on the part? Another cheap down and dirty... If the operator has a few seconds between parts they could hand stamp. One swat will give you quite a few digits with proper backing and a good old ball pean hammer. Most all of the commonly used and readily available marking machines have capabilities of being automated to varying extents where you might be able to put the marker on-line / in-line with your operations...?

  6. #6
    Project Engineer CCR5600Design's Avatar
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    Quote Originally Posted by RWOLFEJR View Post
    Any chance of incorporating a stamp in the processing of the rails? Example... We place stamps in our clamp blocks for a forming operation here. Maybe a break could have the letters or numbers standing proud of the break via an insert and impart your digits during normal operations on the part? Another cheap down and dirty... If the operator has a few seconds between parts they could hand stamp. One swat will give you quite a few digits with proper backing and a good old ball pean hammer. Most all of the commonly used and readily available marking machines have capabilities of being automated to varying extents where you might be able to put the marker on-line / in-line with your operations...?
    My original idea was to have the numbers stamped in on the turret punch or etched in with the laser, but I have been informed by our vendors that this would be a very time consuming and expensive process. We had a couple test panels laser-etched and painted them with the same powder as we will use in this application and the paint completely covered and smoothed over the numbers so they could not be seen at all. The turret punch operation would require stamping one number at a time (apparently, the machines can hold a tool for only one number at a time) so all the number 1's would have to be punched, then the machine stopped, punch #2 installed, etc. so on and so forth for 1 through 0. As for doing it by hand with a ball peen hammer, there will be approximately 7000 sets of these rails manufactured and each rail is to be marked with numbers 1 through 44. If you are volunteering, come on over!

    What we have decided on is to utilize a pre-printed decal and apply it after the painting process. We will also offer the decals separately to replace those in the field that have been damaged, or to retrofit existing frames.


    Thanks for the ideas, though.


    Ron

  7. #7
    Senior Engineer Marky's Avatar
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    Nice Ron...you can't get any simpler than a label.

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    Quote Originally Posted by Marky View Post
    you can't get any simpler than a label.
    Yeah, but...

    Quote Originally Posted by CCR5600Design View Post
    We will also offer the decals separately to replace those in the field that have been damaged
    Is it just me or is that nuts? You are making labels that can be damaged and replaced. How do you know they will order the correct replacement label?

    An anodized aluminum tag laser engraved and pop riveted to the shelf is about as permanent as you can get.

  9. #9
    Project Engineer CCR5600Design's Avatar
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    Quote Originally Posted by PinkertonD View Post
    Yeah, but...



    Is it just me or is that nuts? You are making labels that can be damaged and replaced. How do you know they will order the correct replacement label?

    An anodized aluminum tag laser engraved and pop riveted to the shelf is about as permanent as you can get.
    The label I came up with can be cut to length (from 48RU or 7' down to 1RU or 1-3/4") and will fit any mounting rail we offer. No special tools are required, no rivets are required and anyone with a pair of opposable thumbs can install it. It also costs less than $3 each and can be coiled on a reel of 20 pieces and spooled off as needed. Besides this, the gal who prints them for us is a cutie and I like having her drop by the shop with the orders. Beat that with an aluminum laser-engraved tag! :P


    Ron

  10. #10
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    Quote Originally Posted by CCR5600Design View Post
    Besides this, the gal who prints them for us is a cutie and I like having her drop by the shop with the orders. Beat that with an aluminum laser-engraved tag! :P
    Well Ron,

    I guess I could wiggle my arse a little for you, but is it really worth it just to save you future trouble? Hmmm, Nah, I think not.

    So, we have...
    Labels that can be damaged and replaced.
    Cutie calling that I am sure your wife would not be happy to hear about.
    The $3 labels I could do for $2.50 - sans arse-wiggle of course.

    Seems like you have quite a good grasp on the important things in life

  11. #11
    Project Engineer CCR5600Design's Avatar
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    Quote Originally Posted by PinkertonD View Post
    Well Ron,

    I guess I could wiggle my arse a little for you, but is it really worth it just to save you future trouble? Hmmm, Nah, I think not.

    So, we have...
    Labels that can be damaged and replaced.
    Cutie calling that I am sure your wife would not be happy to hear about.
    The $3 labels I could do for $2.50 - sans arse-wiggle of course.

    Seems like you have quite a good grasp on the important things in life
    We have labels that do not require pop rivets (no product cost, no rivet gun and no additional labor)
    no transportation costs

    Life is good.


    Ron

  12. #12
    Project Engineer CCR5600Design's Avatar
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    Dave,

    Talk to me about your laser-engraved tags...

    Here's what I need:

    A strip measuring no more than 1/2" wide and approximately 78" long.
    Strip must be clearly marked with rack unit (RU) designations from 1-44
    Numbers must be spaced 1-3/4" from center to center
    Between each pair of numbers, there must be a hash mark showing the upper and lower boundary of the RU
    Strip must be easily secured to the mounting rail and must not curl, twist or seperate from the rail.

    ru strip.jpg

  13. #13
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    Hi Ron,

    In order to mark metal, a CO2 laser would need it to be color-anodized aluminum as the laser does not actually mark the metal, it boils the color out of the anodizing leaving a white mark behind. This process forces the aluminum surface back to a just-anodized state before the color was added. This means that water-based color can be applied and the surface sealed again by immersion in boiling water if desired.

    The next issue would be the length of 78". Lasers typically have a vertical lifting Z-axis to accommodate different heights and thicknesses of material to be marked. Common engraving lasers have a bed of around 18" x 24" max. A laser with a bed big enough for 78" would be an expensive machine to purchase so the engravers with such equipment would be limited.

    Having said that, since I built the laser myself, I could actually cut a 2" hole in the outer cabinet at the correct height with the Z-axis for the length to move through as the marking is done. My laser has a mechanical sweep of 17" in it's longest direction, so not too big a deal to locate the strip in 5-stages. A preferred alternative might be five strips that when placed end-to-end made up the 78". That approach might fall in well with the people who do the anodizing as 78" means a big anodizing tank-line.

    Now to the strips themselves. They could be guillotined from any suitable (to you) gauge of aluminum. After anodizing and marking they could be sprayed with a 3M permanent contact adhesive and cover strip. But, other than the marking, I do not have sufficient knowledge or expertise in these other processes. All of the labels I have done have been pop riveted on.

    Finally, I am retired and now just do stuff for fun and a little spare income, and this sounds like a production job that I really would not want to take on. The sunshine, motorcycles and allure of the open road offers too many conflicting joys to consider real work again.

    But, happy to help with comments or thoughts on your project, if I can be of use.
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    Lead Engineer RWOLFEJR's Avatar
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    Just thinking out loud here...

    I can't see a separate piece being attached to the rails being more cost effective than making the marks on the rail itself. The separate piece is going to cost about $?? and about $?? to install these things.

    So I looked up adhesive backed scales figuring you can find out who's making them and have them done custom. The cheapest adhesive backed steel "off the shelf" 6 foot scale was $5.30. So let's say you find a shop to make your custom vertical scales. What sort of quantity will they need to make to get you a decent price and what would the price be?

    So then I go back to the idea of stamping this stuff right on the rails. If we just suppose that we have $5.oo a part that we're trying to beat then this would allow for tooling and labor of 35,000.oo to stamp the 7,000 pieces you spoke of earlier. In all likelihood you won't need to get your return on tooling investment back on that one run of 7,000 pieces. Given that... you can either allow more cabbage for tooling or bring the per piece down considerably.

    Do all the different rails have the same 1-3/4" spacing and just different lengths?
    Are all rails same material and gage?
    Are they the same shape?

    If "yes...yes...yes" then it's easy. Buy an old 6 foot 25 ton press brake (They're a dime a dozen in that size and will have plenty of snot. Should be able to squeeze out the extra 6" for your 78" rails? If not go to a 10 footer.) and tool it up to smack your marks in these things. You should be able to snag up a fine old unit for under ten grand?? Make your "stamps" about a foot long so anybody with a CNC can make them (competitive quotes) and it'll lessen distortion at heat treat. Whip up a holder for your custom stamping sticks and slide them in. If the part is longer or shorter you could have a blank insert etc. to fill your holder or just leave them all in and it'll only strike where there's part. At the base just a straight hunk of whatever it takes to sit the part on and locate it. So holder and stamps maybe around 10,000 even say 15,000. Then allow maybe 5,000 for a regrind of your stamps say every 100,000 hits... drop that to 50,000 even?

    So roughly 25,000 and say at least two parts a minute at a buck a minute. (should be able to make money on that in today's market? Actual in-house cost should be less.) To get all your cabbage out of the first 7,000 pieces you'd be spending 4.07 per rail to mark them. The next 43,000 rails will cost you fifty cents per rail. The next 50,000 after that will cost you roughly sixty cents a rail to mark because you needed to freshen up your stamps. So say the entire first 100,000 rails made is the target for return on investment... then it would be your constant fifty cents labor + ($30,000 tooling divided by 100,000 parts) = 80 cents a rail. With machinery and tooling you'll be able to depreciate...

    If you make a separate piece and attach you will probably have that same fifty cents of labor min. to install the gadget let alone the cost to have it made.

    So the rail is made... then stamped... then coated or whatever you put on them.

    If you have more than one supplier or aren't comfortable having them run your machine located in their house then you ship back and forth. That'll add some additional shipping $$ to the per rail price.

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