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How do you suggest we should do lean in a foundry?

5/22/2012
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Dear Gemba Coach,

How do you suggest we should do lean in a foundry?

The glib answer could be: just as anywhere else – but I’ve done a couple of Gemba walks in foundries and I have to say that I find the environment somewhat daunting. The foundries I’ve seen vary considerably from one another, but one thing for sure: it’s a demanding process. On the one hand the process is quite heavy going – it’s physically demanding, dirty and, well, hot – and on the other precision casting require a sophisticated handling of technical parameters.  This is definitely a case where I would recommend both 5S and a robust six sigma program. One place I would not start is what I’ve seen on a few occasions: kaizen events to eliminate waste by reducing operators’ walking distances. This is not negative, as such, of course, but is unlikely to deliver the hoped for results.

Like most process industries, foundries have large equipment and relatively few workers spread around the place – although I’d have to distinguish the pattern crafting part of the operations from the actual casting side of things. Lean experts coming from an assembly work tend to start with a “seven wastes” perspective and immediately show that operators and parts are moved around quite a bit, which is sheer waste. This is certainly true, but has an element of a solution looking for a problem, like looking for the lost key under the lamppost because the light is there. If you’ve considered starting by cutting headcount costs by reducing operator movements, I’d suggest you take a step back and, well, think. The question, as always, is “what is the problem we’re trying to solve?” and hence, how do we see our real problems as opposed to what is immediately apparent.

The issue with wearing lean glasses in any new setting is that wastes will jump out everywhere, but I don’t have any experience base to distinguish real problems (with a high-pay off potential on sales, cash and bottom-line) from mundane issues (indifferent as regards sales, cash, and the bottom-line), no matter how “obvious” the waste might be, such as operators walking all over the foundry for very little apparent value-added time. For what it’s worth, I do have a standard or sorts to approach lean in an unknown environment:

  1. Safeguard the people
  2. Protect customers
  3. Control the lead-time
  4. Reduce the lead-time
  5. Eliminate costs at the source

 

Forging Ahead Safely

How would that standard apply to a foundry? To start with, we have to accept that a foundry is an aggressive working environment. Those I’ve visited tend to be dark, dusty and filled with very hot objects. I rarely recommend starting a lean initiative with 5S because of the many disappointments with this over the years, but this is clearly a case where a 5S drive applies. The problem we’re trying to solve is not cleanliness per se, but involving operators in improving their own working conditions. Many kaizen workshops tend to be structure heavy with one or two “alibi” operators. In this case, we should think of a workshop plan by and for operators. The idea is to organize events so that every operator of the foundry has participated at least in one event in the year. There is no need for more than one facilitator per workshop, and the idea is to use the 5S methodology with a special focus on safety.

As a plant manger, as you progress through this plan set aside a small budget for “cleaning up” each area touched by the event – fixing what is clearly broken down, a coat of fresh paint, maybe – this should be running costs, not investment. Overall, getting a foundry spick and span is a daunting task, so we break it down in kaizen steps: the ideal is that over one year, every part of the foundry has been spruced up and every operator has participated in the effort to improve the working environment. As a plant manager, you can make a point of showing up at the end of the workshop and personally agreeing to what is feasible and what is not. You’ll find that this will considerably benefit your relationship with your workers.

What’s Kilning Delivery

Protecting customers is of course about quality and delivery. Before we tackle the quality issue, let’s start with delivery. Many manufacturers I know keep complaining about the poor delivery performance of their cast parts suppliers. This issue is not specific to foundries but tend to touch every flow process business, where the batch mentality still rules (mostly because of the difficulty and high perceived cost of change-overs). To understand delivery issues, the first step is to create a group to handle a weekly production plan based on understanding real customer demand. The trick is separating high-volume parts (even in a low-volume environment, you can safely bet that less than ten percent of all product references will account for more than 50% of total volume) from low volume ones, and then schedule the high-volume parts every day. This might (or might not) put a strain on the process flexibility, but it will have the merit to clarify your understanding of real demand. What I usually find is that if you focus on making the high-demand parts every day to a leveled schedule (since they’re high demand, demand variation is overall lower), it leaves ample production time to produce make-to-order one-offs as well.

Secondly: quality. Quality in any process industry is a matter of finding out which are the right parameters to focus on. This is by no means obvious, and certainly six sigma will help. To get started, you can task a technical group to set up SPC tracking of key parameters not, at this stage, to reduce variation, but to figure out which parameters have the greatest influence on quality. Sure, temperature control is important. Certainly, sand quality matters. But this can be true of any foundry. The challenge is to figure out what parameters matter in your specific foundry, and this is by no means obvious.

EPEI vs. MRP

Once you have a better handle on working conditions, quality and delivery, you can start on the next phase, which is controlling lead-time. In the cases I’ve seen this comes down essentially to two key problems (1) getting the right rotation of products through casting and (2) getting patterns in time from crafting. The lean tool to understand crafting programming is Every Part Every Interval (EPEI): the set sequence of parts production so that the lead-time of any individual part can be known. This goes counter to the MRP logic of programming parts according to calculated instantaneous demand, but is hugely helpful in settling down the process and seeking “economies of repetition”. Exploring Every Part Every Interval will also lead you to much better understand how various parts you produce behave, from the high runners to the occasional repeater to outlandish exotics.

Pattern making remains in many cases a craft operation and I’d start there with straightforward production analysis boards to see whether we’re making patterns at the expected rhythm in order to control the overall lead-time. If handled properly by checking the boards several times a day and discussing comments with the pattern-makers, the various causes for production loss should become visible, and highlight the many opportunities for kaizen.

Once lead-time is under control, you’ll have a better idea of what value streams are going through your foundry, and how different parts behave with different lead-time conditions – these different parts need not be treated the same in terms of scheduling – high runners can be pulled, and make-to-order programmed, for instance. Once your management team has clearer ideas about how to handle these value streams, it’s time to bite the bullet and reduce lead-time. In casting, as with most flow operations, this is a matter of increasing the frequency of change-overs – which, in turn, means single-minute exchange of die (SMED), no two ways about it. At this stage I don’t know any other way than finding a local SMED consultant and setting up a robust SMED program with the aim of systematically reducing the Intervals of the EPEI – this will highlight many shortcomings and deficiencies of your technical process, but there’s nothing doing – no pain, no gain.

But what about cost reduction? Keep in mind that the full lean principle is cost reduction by waste elimination. Obvious wastes, such as operator movements backs and forth, are not necessarily high potential wastes, such as poor scheduling. The previous exercises should keep you busy for a couple of years and, more importantly, should lead you and your team to a more detailed understanding of what they key wastes occur in your operation as a result of the way you currently run things. I have no doubt that as you get more expert at recognizing the wastes you create you will also find countermeasures to eliminate these wastes and your costs will come down. I realize there’s something of a leap of faith in this statement, but your costs will come down.

Lean as usual you might say - maybe.  However, the foundry remains a rather extreme environment where people’s involvement is critical, so before you roll out the plan, let me back track to the essential point of starting with a 5S/safety workshop for each operator team and a six sigma project program for technicians. The immediate aim is to get people working together in taking ownership for their physical and technical environment, and work improvement strategies from a basis of teamwork and shared challenges.

1 Comments | Post a Comment
Kate Mackle June 5, 2012

I have been "doing lean" in the metals industry for 25 years, covering processes such as melting, casting, rolling and including foundry operations.  I would be happy to share my experience with you.

You don't say why you want to "do lean".  The common challenge in your industry is to achieve the leadtime and delivery accuracy expectations of the customer whilst struggling with ever-increasing complexity of product: and meeting that demand on equipment that was designed to be cost-effective on a much simpler mix.  Does this sound like you?

Michael has suggested various ideas which address the scheduling of production.  In your environment, a lean implementation must start at the planning level: how do you design a production system which enables you to balance demand with capacity?  You need to recognise the physical characteristics of the foundry process which influence and constrain flow.

As in all industries, it is important for operators to engage in improving their work methods and environment but this will not yield business results on its own.  There are many well-proven methods which lean practitioners in other metals businesses will be happy to share with you if you are happy to network with them.

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