industrial engineering

Taxis waiting for people and people waiting for taxis - reduced

Oct 27 2011

Waiting for each other

We have all seen the absurd situation in the featured picture above of a line of customers waiting for taxis while a line of taxis next to them is waiting for customers, with a barrier separating them. This particular instance is from The Hopeful Traveler blog. The cabs are from London, but the same scene could have been shot in many other major world cities.

I am sure we have all encountered similar situations in other circumstances, which may or may not be easy to resolve. One particular case where it should be easy is the restaurant buffet. Figure 1 shows a typical scene in buffet restaurants, with a line of people waiting to get food all on the one side of the table, while food is waiting and accessible on the opposite side.

Figure 1. A typical buffet

I think the fundamental mistake is the assumption that a buffet is like an assembly line, providing sequential access to dishes. This means that you cannot get to the Alo Gobi until the person in front of you is done with the Tandoori.  The ideal buffet would instead provide random access, meaning that each customer would have immediate access to all dishes at all times. While it may not be feasible, you can get much closer to it than with the linear buffet. The following picture shows an alternative organization of a buffet in circular islands that is non-sequential.

Figure 2. A buffet island at the Holiday Inn in Visalia, CA

The limitation of this concept is that replenishment by waiters can interfere with customers. To avoid this, you would want dishes to be replenished from inside the circle while customers help themselves on the outside, as in the following sketch:

Figure 3. A buffet island with replenishment from inside

One problem with the circular buffet island, however, is its lack of modularity. You can add or remove whole  islands but you cannot expand or shrink an island, which you can if you use straight tables arranged in a U-shape, as in Figure 4.

Figure 4. Buffet island with straight tables

This buffet island may superficially look like a manufacturing cell, but it is radically different. Its purpose is random access to food as opposed to sequential processing of work pieces, and the materials do not flow around the cell but from the inside out.

Such are the thoughts going through my mind while munching on the Naan at Darbar.

By • 3 • Tags: , , ,

Steam locomotive and typewriter

Oct 25 2011

The steam locomotive and the typewriter

The first draft of my book  Working with Machines contained a chapter that was a post-mortem on two obsolete machines, which was cut on the grounds that, unlike all other chapters, it was not actionable for the reader.

Its abstract is as follows:

The steam locomotive and the typewriter are icons of the industrial age, and their parallel histories show different aspects of the human experience of working with machines. The steam locomotive is fondly remembered; the typewriter, all but forgotten except for the QWERTY keyboard. The steam engine participated in the development of every industrial economy, but the typewriter played no major role in Japan. The typewriter did not demonstrably improve the productivity or quality of office output, but was adopted only because of its image of modernity.

Locomotive driver was a prestigious position for a manual laborer, but typist never was. Compared to electrics and diesels, the steam locomotive had a cab that was exposed to the elements and to the heat of the firebox and therefore uncomfortable, difficult to operate, and dangerous. Yet engineers and firemen preferred it to the tedium and loneliness of modern locomotives. Automatic machines that require human attention only when they malfunction are also in airplanes and in manufacturing plants, challenging the job designer to keep the operator alert and used efficiently.

As the typewriter prints one keystroke at a time, typists were always busy with a single machine and determined both its productivity and output quality. Typists worked in comfortable places, but under pressure, and faced the long-term hazards of sedentary work. The typewriter’s main legacy is that a society can make a long-term investment in machines whose tangible benefits do not obviously exceed their costs.

Click here for a pdf file of the entire chapter.

By • 1 • Tags: , , ,

Dashboard assembly stations

Oct 23 2011

Why production matters

On LinkedIn Lean Business Process group, Ralph Bartelmann asked the following:

Is it really the matter to squeeze the last cent out of production ? In many environments production costs represent a minor part of the over all product cost. Following Pareto reasoning it seems more reasonable to work on other parts of the value stream like supplier developpement, product design etc. What is your opinion and experience ? What are the real challenges ?

Following is my answer:

It’s not about what production costs  but about what it does for the business. Improving production is about making is faster, better, safer, less tedious,… and cheaper.  It needs to be faster to make you more responsive, better so that production does not introduce defects that harm your reputation, safer and less tedious so that you can retain your work force and grow its skills.

If you improve on all these fronts, guess what? Your costs go down, and not only in production but in other parts of the value stream too, because they are not independent of production. For example, there is no point in trying to develop just-in-sequence suppliers unless you practice leveled-sequencing (a.k.a. Heijunka)  in your assembly line.

A manufacturing company ignoring production is an army ignoring combat on the grounds that more money is spent moving soldiers and keeping them supplied.

By • 0 • Tags: , ,

To get to Dublin, you don't start from here

Oct 22 2011

Kaizen without prerequisites

Question from Pedro Burgos: You have an assembly line where ‘Standardized Work’ is not utilized. The operators have ‘work instructions’ and follow them. They do not miss steps. But there are differences between operators in how the work is performed in terms of sequence. All of them perform under takt time, some more than others. Due to ‘wastes’ of motion. You are asked to do a Kaizen to reduce inventory quantities and space. Inventory quantities on the production floor varies, some parts have 3 days of inventory, some have 2 days, some have 1 day (16 hours). The goal is a ‘kanban’ of 2 hours of inventory in the assembly line. Do you think is possible to do this Kaizen? (Discussion in the LinkedIn Global Lean & Six Sigma Network)

Your question reminds me of the old story about asking a farmer in the countryside of Ireland how to get to Dublin, and getting the answer that “you don’t start from here.” In fact, regardless of its current state, a production line can always be improved.

Looking further at the way you describe the challenge, however, several things disturb me. First, while Kaizen, meaning improvement, is always possible, “a Kaizen” seems to designate a Kaizen event, a project template which is not always appropriate. Second, your description suggests opportunities for productivity and quality improvement, but neither is stated as an objective.

A top-down mandate to use a particular method to pursue two goals like inventory and space reduction does not strike me as a recipe for success. Instead, someone needs to do the following:
1. Take a close look at this assembly line.
2. Identify improvement opportunities in all dimensions of its performance.
3. Select one or two to pursue in priority based on improvement potential, technical feasibility, and human feasibility.
4. Determine the project management approach based on content, rather than the other way around.

This approach is much more likely to achieve the desired inventory and space reductions, among other improvements, than just running a Kaizen event to pursue these objectives directly and exclusively.

By • 1 • Tags: , , ,

Continuous improvement from bolts to clamps

Oct 19 2011

The Role of Technology in Continuous Improvement

In an article on this topic in Industry Week today, Ralph Keller asserts that Continuous Improvement is focused on business processes rather than technology.

However, if you wrap tinfoil around the feet of a welding fixture to make it easier to clean, replace bolts with clamps on a machine to reduce setup time, or mount a hand tool on the machine on which it is used, it usually counts as Continuous Improvement but involves technical changes to work that I don’t think anyone would describe as business processes.

Yes, Continuous Improvement is done without expensive technology, but it does involve cheap technology.

Ralph Keller also reminds us that Continuous Improvement is not “rocket science,” which implies that it is easier. I agree that it is different, but not easier. I don’t know any rocket scientist with the skills to facilitate Continuous Improvement.

By • 0 • Tags: , , , ,

Speaker competing for attention with laptops, reduced resolution

Oct 16 2011

Meetings, seminars, and laptops

Communicating face to face is supposed to be more effective than electronically. Yet it is common today to see professionals travel thousands of miles to be in the same room and then engage in parallel play on their laptops while one of them is giving a presentation. The speaker stands in front of tables arranged in a U, facing a wall of open laptops. The people behind are silent and focused, and seldom make comments or ask questions. They appear to be taking notes, but in fact, they are completing an unrelated budget spreadsheet, checking emails, or playing solitaire.

It takes the presentation skills of a Steve Jobs to successfully compete for attention with the rest of the world coming to each seat through the web, and most speakers do not have these skills, especially when in a foreign language, and it is also quite possible that the information they have to convey does not lend itself to an entertaining presentation, but today’s business audiences make no allowance for this.  The notion of giving each person a polite hearing, as taught in elementary school, is gone.

The intrinsic discourtesy of this behavior, however, is not the main problem. By providing escapes,web-connected laptops make badly-organized, boring meetings bearable, and allow them to continue unchallenged. Possibly the most tedious of all business rites, the regular staff meeting involves members of a department standing up one after the other and giving a status update on issues that are usually of interest only to themselves and the manager. Without laptops, some members would fall asleep and snore, and others would eventually rebel against this waste of time. And this would lead to a positive change. Wired in to their laptops, they don’t challenge the status quo.

A few years ago, cell phones routinely disrupted meetings,   with their owners leaving the room to take the calls, which were obviously more important than anything the people present in the flesh might have to say.  Today, cell phones disruptions are abating, as meeting participants usually comply with requests to turn them off, or, even better, to “turn them back on at the end of the meeting, so that they don’t miss their important calls.” The current situation with laptops, however, is not sustainable. It is a technology-induced problem, that technology may actually solve. Laptops are an endangered species, likely to be replaced with tablets that do not provide the same kind of visual shield as a raised laptop screen. Already today, people who bring iPads to meetings actually participate in the meetings, as doing otherwise would be too conspicuous.

By • 0 • Tags: ,

«‹ 5 6 7 8