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01-21-2012, 01:56 PM #1
Why do cnc back gauges cost so much?
And why has China not marketed a cheap version of them yet??
Or, why hasn't someone done a DIY version??
01-21-2012, 02:04 PM #2
Do you want one?
If you're posting this because you are in the market for one, send me a PM with contact info..
I have a customer that has asked me to help him sell a , new in the box, one he has had for years. If he has not tossed it by now I'll hook you up with him so you can see if it is what you need.
01-21-2012, 02:19 PM #3
01-21-2012, 03:36 PM #4
I think its the classic reasons-
-huge variety of machines that they must fit
-extreme workplace conditions means they must be really tough
-actual costs of designing, manufacturing, warehousing, marketing, shipping, and stocking repair parts and providing service is far higher than most people think
the fact of the matter is that DRO's, real ones, cost over a grand for similar size ranges.
assuming you are talking about back gages for brakes and shears, they are pretty much worthless unless they go at least 96" of travel, and, really, 120" is needed from most shops- cause thats the sheet size you work with- 10' in length.
Add in actual motors, which move the gage, that a DRO doesnt have, and, in small quantities, I think you arrive at about the price they sell for-
Tiger Stop, which is the smallest, cheapest, most versatile model out there, sells for around five grand for a basic unit, which isnt really enough for sheet goods- its designed for linear materials.
Save Money with Automatic Pusher, Stop Gauge | TigerStop
If you really think you could make one for less, and make money, jump right in- I sure dont think I could, unless you were selling thousands a year.
And, of course, it would have to somehow fit about 2000 different models of obsolete shears and brakes that havent been made in 50 years, each with different configuration problems.
As for mach 3- doesnt that run on PC's?
I know that if I was buying a CNC back gage for a shear, the LAST thing I would want is it to require a laptop. I want hardened dedicated electronics, in a nice dustproof metal box, with no way the guys in the shop could change anything.
A separate PC running your backgage sounds like a recipe for disaster to me.
I suppose, for a home shop- but how many home shops have 10' shears?
01-21-2012, 06:48 PM #5
All i can say is after the 2 cnc press brakes i have encountered in the last 6 months the last thing i want is one that runs on a dedicated controller like the amada i have been using a lot! Firstly a standard key board is nice, not a poxy tiny membrane pendant. USB that actually is USB not just a cloned locked dongle to store only another 60 programmes on the controls 60 programme limit. A file format on the USb that can't be copied off onto a pc and chosen programmes restored back to the press controller with out a fortune spent on a custom bending programme and a network interface costing over 1K to have installed. No ability to add any notes to the programme. A 6 digit long programme name limit. Pritty much all limits that dissapereard in the pc world before even the 386 processor became common.
At least EMC would give you a easy 1 terra byte+ storage, with a programme probably being sub 1Kb that's more than a lifetimes worth of programmes. File names limited to 26 digits long. A system that could be backed up and reinstalled on a new machine in sub 30 minutes and cost less than £300 to replace. A keyboard that you don't need to pencil sharpen your finger tips and tap away at like a old wood pecker. Do a awkward, unmentioned apart from one note in the manual 2 button press to get letters, which you have to monotonously scroll through and select. Oh and not lock up every 5 frigging minutes on a machine that's only 4 years old. I mean, i have a EMC2 ed Bridgeport, to date after 100's probably 1000's of hours i have never had EMC2 lock up or crash!
Now the actual back gauge when it works is a good solid bit of engineering. Very solid, very reliable and some nice ball screws. All on nice linear guides. Problem is theres no lubrication fittings, no oil pump nothing zilch. There std procedure is to use spray grease. Hello there's wipers on all of the frigging bearings, if the grease can get in , the bearings are going to be hosed in no time. If the wipers work eventually the bearings are going to run dry. Really bad over sight that one is! That said, it would not be cheep to buy even that much linear guide + ball screw hard wear even to diy your own version for a simple 2 axis set-up with just manually positioned actual stops.
Add in that the frigging stops have some really usefully steps on them to use as datums, not just the front of the stop. But you have to either measure them and manually apply the offsets or dig into the manual. Why the feck they are not a option in the so called conversational control during programmeing is beyond me. Don't even mention trying to adjust the nip when you want it to move the back gauge before bending, not possible!!!! Equaly impossible is to not get the back gauge to come back in intill the parts out of the way, been removed. With out reprogramming the sheet thickness, that stuffs all the bends you have then adjusted.
Hence theres no way in hell i would - could ever recommend the thing i have been running. Its just too damn clunky. Even the worst of the cnc "unmentionable" websites retrofits could not be worse from a operators point of view. There now contemplating upgradeing to something of chinese origin. A nicer control, double the tonnage and half the cost.
The shear i use a lot at another customers would be awesome with a cnced back gauge. Being able to store programmes and call them up for repeat parts could - would really speed things up. You only need about a 2' back gauge on a 8' shear to do a lot of cutting. More would be nice, but you then need some kind of support system to avoid - support the plate drooping under gravity. its only a 1/8" capacity shear, anything under 2mm will easily droop enough to miss the bottom of the stop that far back! Some of the better shears out there do have support systems, but unless your really doing that kinda work its probably over kill, would be nice though :-)
Ries, firstly the std pc does not have to be sitting out in the shop environment. It can be interfaced easily to the point that the machine won't work with out it being ready. That's really easy to do, and with the simplicity of what its controlling way way simpler than a cnc retrofit of say even a simple 3 axis mill. Equaly the pc can be interfaced the other way so it knows when the machines in e stop and keeps track of things just as well as a dedicated controller can. It end up being just like a embedded control, just like a PLC is interfaced in. If done right, it becomes part of the machine, not a abortion like add on! Whats more it easy to do, and can be done for a lot less than $50. Only takes a few simple options to be set right in EMC, not sure about mach but i believe its the same, just gotta tell it what pins on what ports are inputs not outputs :-) And then what they control.
01-21-2012, 07:41 PM #6
i have been using a diy backgage for ten years now. first used turbocnc. now mach3. this is on a 14' 180 t pearson . used 3/4" ballscrews , 2 320 gecko drives and 2 servo motors reduced to 3-1. get 6 ips rapids. have a 2x6x 1/4 rectangular aluminum tube with adjustable stops.
01-21-2012, 08:27 PM #7
Ok, I am curious- what do you figure you have in a Mach 3 system with ball screws, gecko drives, and servo motors. Including a PC, of course.
Is it really little enough that you could double or triple it, and sell it for that price?
Cause nobody makes money selling something for the cost of materials.
My wife tells me I should get a minimum of 5 times materials, but I figure 3 times is a bare minimum.
In reality, real factories usually try to keep materials to around ten percent of selling price, assuming its not some intensely competitive arena like consumer electronics.
01-21-2012, 11:09 PM #8
Watch it there Adama and najnielkp, what you are proposing could never work in Ries's world....MUST BE REAL INDUSTRIAL CONTROLZ!
The laws of nature say a PC could never survive in a shop!
And the rumors that there are hundreds of guys using MACH and a PC to run cnc plasma cutting
machines must be just propaganda!
najnielkp......any chance you could share more on your setup and possibly post some pictures....??
01-22-2012, 01:36 AM #9
Heat and dust, especially conductive dust, are the enemies of circuits, regardless of whose name is on the case or the motherboard. PC level components dominate the market, and even things like Okuma's OSP controllers are PC hardware, albeit in the "mil-spec" form. (Or so Okuma once told me.) There are lots of really good reasons to do it this way.
Fans are a leading cause of PC failure - they suck in dust, clog, stop sucking air, and trouble follows. Fanless PCs are an obvious solution.
So a proper enclosure (with big filters you can easily clean) and a sensible hardware/software configuration (you don't play games on your controller, you don't want viruses on it, etc.) are required. But this is not frontier stuff.
My siemans 810D shows a DR-DOS flash screen at boot, I think the Heidenhain shows Linux. Centroid is also Linux. None of those are magic, none of them are "real time". But all they do is load the right config.
E-stop is a separate thing, and has to be, since ANY controller as complicated as even a 386 can "stall" in too many exciting ways.
Software practices are important - I hear every so often about old stuff that is very hard to get to work because it depends on timing loops of a particular CPU, and other such practices. They were never reliable to begin with, they worked by chance, and now they're very difficult to get to work at all. So your controller might need some good external hardware to report events, timing, and so on. USB may or may not cause problems in such applications.
As for the costs and market, I think Ries is spot on. What's more, I'm working an application where the backgauge will be a fixed manual thing we fabricate - you walk from station to station (all of 2 ft, small brake) and the gauge never moves. It occurs to me that this sort of trick is common where the "mix" is low.
I'd also like to see pictures, notes, and costs associated with shop made back gauges.
(And you call know that Hurco started as CNC back gauges, right?)
01-22-2012, 06:17 AM #10
2 rolled ballscrews and nuts ,pick your supplier, roton, mcmaster. with gecko drives motors and old pc maybe 1000.00 total. i will take pics when i get back to the shop.
the statement that a pc wont survive in a work place? i have 4 . only replaced them when i upgraded to mach.
1 is mounted on the carriage of a plasma cutter.fanless atom board with 32 gig compact flash drive.
you can use mach3 as demo . you will never have a pressbrake gcode file with more than 500 lines of code.the great thing about mach3 is its adaptability.create your own screen, use a touchscreen, pushbutton control panel, or keyboard.
01-22-2012, 07:42 AM #11
Theres a lot more than just ball screws on the amada setup at work. For x you have a carrage effectively at each end running on 2 linear rails. 4 bearings each carrage. R axis, up and down on the stops again has multiple guide ways and a screw each end. Hence there's a fair bit of hard wear there. Add in Belting to link the 2 ball screws on each end of both axis, cable chain to go from stationary to the moving R axis and there's a lot of bits. Amada though has done a really nice job on it, and all of it mounts, is built out of some nice custom extrusions. Its very solid, very accurate. You might get away with single ball screws with only a 4 ft press break, but no way on anything larger and still keeping the travel square and solid.
As to the pc, a fan-less one is not essential so long as its mounted in a large enough enclosure to dissipate the heat. Whilst its true its hard to make a pc run in real time and control things, its pretty easy these days to get it so near its darn near irrelivent for gauge positioning applications like this. E stop does - must indeed not be dependant on the pc, it must be physical power disconnect. But its still possible to signal this to the pc, stop the drives and disconnect them all with out losing position.
Making this as a fit any machine assembly and selling it commercially is a diffrent ball game. My gripe is the leading manufacturers of the machines are doing such a poor job on what they supply with a new press brake. When its so easy to do so much better.
01-22-2012, 08:28 AM #12
wow. need to link the 2 screws? linear rails are not difficult why make it so complex? i am just talking about a single axis back gage. thats the problem with this forum in that there are too many that will critique a simple solution to a simple requirement.i have been a lurker for many years . all the so called experts have to spout off about an idea because maybe they are not capable of original thoughts? go ahead and buy a 20000.00 back gage then. become dependant on proprietary software . while i can be back up and working in an hour you will be whining for support from the manufacturer. if they are still in business.sheesh!!
01-22-2012, 11:08 AM #13
naj, there are many "london's" on Earth. Can you add more info to your location profile so that your location is not meaningless ?
01-22-2012, 11:14 AM #14
A single axis is not enough on a press brake, it's not a case of being a expert or sprouting off. If you want to bend a lot of parts, with something akin to a joggle but further apart, in all but the thinnest of materials you need to change the height of the back stop, aka 2 axis required. Same if you want to run different height bottom tooling. All the more so if your work also includes short bends that see the back stop coming up on top of the die.
If all your bending is so simple it can be done without these requirements, great for you. But there's a lot of us here that have do do something a lot harder than simple 90 degree bends in nice thin alu. Start getting into 6mm+ and multiple bends were you need the stop to register against a previously bend flange and you may well also need the backstop to move after the material is pinched so the work does not swing up into it.
Add in requirements like being able to run both euro bottom tooling and older tanged tooling and its harder still. last week i was bending 30mm round on a custom made roller V in the same machine. That part required the back gauge to come up darn near to the height of the bottom of the top tool when its fully open! Simple is just not enough.
That said its still perfectly within the capabilities of anyone here to make one. With out the infuriating cripples the propriety ones come with. Weather you can sell them and be competitive is a whole nother ball game.
Linear rails are not hard to make, but there not free either. If your running a break with a 8' 100+ton capacity then its gotta be darn solid to not get knocked out of true even with delicate manual loading.
If you want to discus delicate home shop style automation based around small simple guides and all thread for lead screws, this is not the place. This forum is the place to discuss industrial applications. See the forum guidelines.
01-22-2012, 11:31 AM #15If you want to discus delicate home shop style automation based around small simple guides and all thread for lead screws, this is not the place. This forum is the place to discuss industrial applications. See the forum guidelines.
And I want to discuss ALL ASPECTS of this topic.
My main application would be a 17-48 Diacro hydro-mechanical brake.
Amana, I think you're trying to twist it into a Home Shop slant, and I think
najnielkp's application is not that at all.
najnielkp....I am eagerly awaiting pictures of your setup!
Which London are you from?
01-22-2012, 12:38 PM #16
01-22-2012, 12:55 PM #17
Btw, what year and model Amada do you have?
01-22-2012, 01:08 PM #18
01-22-2012, 03:49 PM #19
really? you need to do reverse bends? and thin parts? and make the gage move before bending? so do i and all works with mach3. oops !! did i say the diy word?
01-22-2012, 05:13 PM #20
So how do you adjust the height of the backstop then? Enquiring minds want to know! As presumably it must change in height to catch the part in the right places to perform reverse bends, account for differing tooling? Would realy like to see some pictures. Sorry if my post seamed strong, just i'm so pissed a modern sub 4 year old machine costing £60K+ could have such good mechanicals and such a frigging crippled control system.
As to the lubrication issues, im sure some could be added, but the machine in question is probably just not going to be there long enough to make it worth our effort. Also it uses round guide bars with the semicircular linear bearings, hence any grease nipples would have to be installed through the carriage mounting blocks, not easy and would require complete disassembly. Equally the R axis spins the nuts not the screws, hence i have not looked to see if you could even remotely gain access to add lube points. I can't remember the model letters but its a 25-80 Amada circa 2-4 years old. I think it's the base model, non graphical interface, but it just could - should be so much better for next to no real additional build cost. 60 programmes and a further 60 on a USB pen don't go far in a laser cutting jobbing shop were your doing some 5 diffrent parts every day of the week. The fact that you can't use a off the shelf std USB stick is what really gets to me. Add in the unstable operating system and it's disappointing.