retrofitting hydraulic press brake

stasis · Jun 29, 2005

Ok, just got into the swing of this new job & already handed a project. This is a hydraulic press brake used in metalforming. Brakes .099 to .018 galvanized, aluminum & stainless. Currently, this brake is controlled by proprietary electronics & relays, and overall consist of 30 + printed circuit cards, a monitor, 40-50 relays and a foot pedal. 4 visits from the techs cost more than the retrofit pricetag, so I was given an ok. I intend to swap to a HMI & a ML1200 w/ analog expansions. The hardware is easy, I'm just curious if anyone has tried/done this type of machine before, and what are some things I should keep in mind...

rsdoran · Jun 29, 2005

Since its a hydraulic press I would go with a Safety PLC and/or safety rated equipment, possibly the Guardmaster but it requires different software than an ML.

May want to look at www.sti.com at the info they have.

I assume you will be including light barriers on front and back that can allow the material to feed but a hand etc would prevent from starting?

When you convert this from factory specs then you and your company are fully liable for any accidents that may occur afterwards. Look at OSHA regulations concerning hydraulic presses. www.osha.gov

stasis · Jun 29, 2005

there is a curtain on it now, and across the back there is a pull-cord style safety switch to prevent access. I was planning on only changing out the 'brains' of the machine, not the brawn. I planned on replacing the relays/monitor/cards with a HMI/plc. The physical parts like the pressure switches/scales/safetys will be left intact.

Thanks for the info on the OSHA regulations...I'll be looking closer at that stuff since the machines were built in the mid 90s in Europe.

TConnolly · Jun 29, 2005

AB has a canned soluiton for presses based on two ML1500s set up in a redundant safety configuration. You might want to check it out.

mgvol · Jun 29, 2005

Ask your AB distributor about getting a quote from Rockwell's Metalforming Automation and Safety Systems group. They have turn-key retrofit control packages and will quote a base system (which is pieces/parts), and will break out all of the options/adders. It is based on a redundant MicroLogix system, the program is written for you and locked out from modification, and they even have an option for a fully-assembled system package with so many hours of start-up engineering support. It meets the requirements of:

[font=Arial,Arial]OSHA 1910.217 [/font][font=Arial,Arial]

ANSI B11.1 (2001)

NFPA No. 79 (1997)

CAN/CSA-Z142 (2002)

Alaric, you beat me to the punch!

[/font]

Stephen Luft · Jun 29, 2005

You will require two control systems.

One for the automation

One for the safety to meet OSHA and ANSI requirements. The key is redundant processors and safety relays.

We provide information for a product that was designed to be used as either an OEM addition or a retrofit for an existing press.

The second link is an application article that talks about both automation and safety upgrade.

http://www.entertron.com/einl/app5.htm
http://www.entertron.com/cm1805as.htm

The AB solution, although good is quite expensive. The first link will give you an example of what our customer was able to accomplish. They also considered AB as well.

Hope this helps.

God Bless,

glaverty · Jun 29, 2005

Start Reading

If you don't already have them get yourself a copy of Ansi Regs B11.2, B11.19, B11.TR3 and OSHA 1910 and read them.

You should check out B11.2-6.3.3 and A.4 and you will understand why simply using a PLC is not going to meet OSHA/ANSI Requirements.

David A. · Jun 29, 2005

You may want to look at Efector's E-Controllers you can do the control and safety with one controller.

stasis · Jul 4, 2005

ok, I've searched the osha site & can't find info on hydraulic press brakes. The reference to OSHA 1910.217 states in the exclusion section 'press brakes', so this is no good.

Why wouldn't I be able to use a ml1200 or 1500?

rsdoran · Jul 4, 2005

What you may want to do is a "Risk Asessment", this can determine the level of safety required. This may help: http://www.sti.com/pdf/OH_LOPAeprint.pdf

You may be able to use an ML for the project but you also may need to use safety relays and redundacy in the process. The idea is to prevent anyone or anything to be harmed by the process, not just the operator.

As I mentioned STI offers an abundance of information specific to safeguarding and safety for different processes. http://www.sti.com/

As was mentioned there are several "canned" systems available for this kind of project that can eliminate many (if not all) the issues pertaining to safety.

The fact that there is a "light curtain" implies some level of safety is required. If you are not fully familiar with the issues then you may want to consult with someone to verify all concerns are being addressed.

JohnW · Jul 5, 2005

Look at this http://www.plctalk.net/qanda/attachment.php?attachmentid=4380

stasis · Jul 5, 2005

thanks for being so safety-consious, rsdoran...wish all in our field were.
The programming won't be that difficult, as I actually have the original paperwork that came with the machines.

I was referring to the post by Stephen Luft that said I'd need two control systems. When retrofitting a machine, I always put safety controls ahead of the actual process. These controls are hardwired, with secondary inputs back to the controller. In the program, these inputs are required for operation. Why two control systems/redundant processors?

rsdoran · Jul 5, 2005

Why two control systems/redundant processors?

Some systems require.

Maybe this will give you a better idea since it directly pertains to your application.
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9836

http://www.sti.com/products/LazerSafe/index.htm

This page offers different circuit examples and links to a variety of safeguarding guides.
http://www.sti.com/safety/index.htm

The "issue" I see is that once you modify this machine then YOU and your company are fully liable in case of an incident. The modifications should "meet or exceed" TODAYS safety/safeguarding standards to minimize possible liablility issues. It may not be "prudent" to use the existing safety features and modify the control system. I am sure the last thing you want to happen is modify it then an accident occurs.

The last time I did something similar I had to monitor all kinds of things to fulfill the safety issues. Just take time to be aware of all the issues and how to manage them.

glaverty · Jul 5, 2005

stasis said:
Why wouldn't I be able to use a ml1200 or 1500?

Did you check out Ansi B11.2? Your probably going to have to buy it.

http://global.ihs.com/doc_detail.cfm?currency_code=USD&customer_id=21254234280A&shopping_cart_id=2825582F2E4A504C495B3D34310A&country_code=US&lang_code=ENGL&item_s_key=00007101&item_key_date=941231&input_doc_number=B11%2E2&input_doc_title=

rsdoran · Jul 5, 2005

I meant to recommend that you get NFPA 79.

retrofitting hydraulic press brake

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