Ye Cannae Change the Laws o’ Physics!

So what have dodgy sets and actors with their trouser legs tucked into their boots got to do with change?  Quite a lot actually.

Scottie was right and, although you might not think it, change follows the laws of physics.  This is why it often doesn’t work.  The villain in the piece is entropy and for those of you without a degree in physics I’ll explain.

Entropy is the term that describes how things tend to degrade and become less ordered.  Why food decays, buildings crumble and, ultimately why the universe will run down like a neglected clock. One of the best examples I can think of is knots.  Any piece of thread or rope is prone to tangles, just ask any fisherman or knitter.  Knots are highly ordered tangles and we can design a knot to have the properties we desire: to be secure, but able to be untied easily; one which we can tie one-handed; one which we can tie quickly. When tangles occur they don’t form a recognisable knot because there are infinitely more disordered knots than there are ordered knots.  Tying an ordered knot takes energy (those of you who have learnt to tie a bow tie will understand) and it always takes less energy to untie a knot than it does to tie one.  Conversely, it always takes more energy to untangle a rope than it does to tangle one.

Organisational change is something we do to make our organisation more ordered.  It goes without saying that implementing change takes energy, but I am constantly amazed at how often people fail to realise that it takes energy to maintain the changes once they have been implemented.  In fact I’d go as far as to say that it’s almost impossible to maintain a steady state and that the best you can do is to maintain a state of constant, gradual change – Kaizen.

So what’s the best way of keeping change on track? I’d suggest two strategies.  The first is what I call “paying attention”.  By this I mean making it obvious that you’re committed to the change process, by walking the shop, by commending good behaviour and by confronting bad behaviour.  The second is by making sure that your first line managers are totally on-board and by equipping them to answer all those difficult “why” questions that they will be asked.

Good luck, and don’t split too many infinitives!

Posted in Change, Lean

Painting by Numbers

I was asked by a client to have a look at their production process.  The main problem seemed to be that the paint shop was a bottleneck and at busy times they struggled to get the throughput they needed.

The current state process map was interesting:

  • The paint system had a 12 hour curing time and they couldn’t afford an oven to speed the process up.  This, coupled with the availability of drying racks, defined the maximum throughput we could achieve.
  • Because the product was awkward to handle the painter needed help at busy times to allow him to concentrate on the value add task of painting.  There was no definition of the load above which the painter needed help.
  • The painter was responsible for cleaning down the surfaces prior to painting.  When we looked at this process it was obvious that there was a lot of variability in the cleanliness of the components when they arrived in the paint shop and sometimes it took longer to clean the components than it did to paint them.

As I was facilitating the “Analyse” phase of the DMAIC I gave the team a couple of gentle pushes: one towards taking the variability out of the process so that we could plan effectively and one towards defining the inputs to the painting process.  In fact the SIPOC (Supplier, Input, Process Output, Customer) was the key to removing the variability.  The upstream processes were supposedly responsible for ensuring that the components were clean when they were delivered to the paint shop, but there was no definition of what this meant.

We came up with a simple planning sheet that allowed the production manager and the painter to build up a daily plan.  The sheet consisted of a simple matrix in which the job number, component and colour could be entered.  Part of the matrix was shaded and if jobs had to be entered into this region then the painter would need help.  The production manager then used this sheet to pull work into the paint shop.

We provided lint free cloths and a degreaser for each of the upstream processes and modified their SOP to include a definition of what a clean component should look like.

Lessons learned

Defining the inputs to a process is often the key to making it more effective.  Carrying out a SIPOC analysis ensures that the inputs are correct.

Once we’d defined the inputs all we had to do was create a visual plan for each day and define the load above which the painter required assistance.

Understanding the capacity of the paint shop and pulling work into it made the whole process a lot easier to manage.

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Posted in Lean

Long Train Running

Or, how to do a pull system in a small batch, high variety environment.

I’ve been working late, but before I go home I nip down to the shop floor for a quick look.  As I walk into the machine shop I come across Tim, the QA manager, standing to one side with a vacant look on his face.

“All right mate?”

He looks at me.

“Choo choo.”

I take a step back.  Obviously the pressure has been getting to him lately.

Tim laughs and explains that he’s been trying to work out how to do a pull system for our product and had been wondering if delivering components via a train of wheeled pallets would work.  I’ve been thing about a pull system too so we go back to my office and get to work. 

Two hours later we’ve got the bones of a workable system thrashed out.  It doesn’t involve trains, but it does work well and I’ve used it in a number of companies since.  So here it is:

Typical Product

Our product was engineered to order from a mix of bought out and machined in house components.  Average customer batch size was about 1.6 so typically items were ordered in ones, twos or threes.  Because of the high variety, machining routes varied greatly from component to component and the machine shop operated largely as a jobbing shop.  Think pumps or valves and you won’t be far off what we did.

How we organised

We broke each order line down into two kits: a kit of raw materials for machining and a kit of bought-out finished parts.  If an order line was for a two off we split this into two sets of kits – ie no batching.  When we first set up the system we didn’t start any machining until we had a complete kit of bought-out finished parts and a complete kit of raw materials.  Our TACT was 16 finished items per day so we planned to issue 16 kits of raw materials per day to the machine shop.

How we ran it

In the company in question we had a pretty well defined bottle neck process in the machine shop.  We put a Kanban in front of this machine (a large CNC machining centre) and used this to pull kits into the machine shop.  In other companies with less well defined bottlenecks you might consider feeding  kits in at the TACT rate. 

Components that were processed on multiple machines were taken by the operator to the next machine on completion of an operation.  Occasionally small queues would build up where routes intersected, but these rarely caused problems.

On completion of the last operation on a component it was placed on a pallet next to the bought-out finished kit. Once the last component (almost invariably the one machined on the bottleneck)  was placed on the pallet the two kits of components were placed in the assembly buffer and pulled from there into the assembly shop.

Spares and sub-contract

These two are always difficult to manage.  Here’s how we did it:

Spares that went through the bottleneck machine were issued in the same way as raw material kits and pulled in via the Kanban.  Care must be taken to ensure that these spares are well spread out so as not to dry up work for non-bottleneck machines.  Spares that are machined on non-bottleneck machines are pulled from a separate buffer by the operators and used to fill the gaps between raw material kit components.

Some components had an initial machining operation followed by a subcontract operation (eg chrome plating) followed by final machining.  These components were issued to the machine shop with the spares for the first machining ops, had the subcontract ops carried out and then issued with the raw material kits for the final operations.

Handling the evil that is set up

In a high variety environment set up is always an issue.  We found that the benefits of the way we worked always outweighed the disadvantages of a little extra set up.  We also used SMED techniques to drive down set up times.

Supply chain issues

Pushing components into the shop tends to hide supply chain issues.  The machine shop is always busy machining components, but assembly is always starved of stuff to build.  Working the way we did exposes supply chain issues, resulting in many incomplete raw material kits, but once kits are complete they move rapidly into assembly and so on to the customer.

Benefits

Product lead time was reduced from 28 weeks to 18 weeks (there was a long procurement time for special castings)

WIP was reduced by 90%

Product could be despatched within one week of issuing a machining kit

Overdues dropped by 80%

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Posted in Lean