Low-Cost Mockups and Layout Trials

Why it matters

Two points that are close together in a layout drawing may not be easy to reach in physical work. The part in the worker's hand can block the view, a full bin can narrow the approach path, or finished product can pile up in front of the new part. A low-cost mockup explores these relationships before the investment takes its final form. Cardboard, a simple stand, scaled floor markings and safe part representations can be used. The aim is not to build a showy model that imitates the real equipment. It is to act out the design question with enough accuracy. When material presentation, working height and pick-and-place points are not represented, a good-looking model can create false confidence.

The trial does not measure only walking distance. The work sequence, view, part orientation, use of two hands, inspection point, replenishment and product changeover are assessed together. If a shortcut requires the worker to carry the load while turning or to reach into a hazardous zone, it is not a feasible solution. Reducing distance does not reduce time in the same proportion; the nature of the remaining motion may have changed. For this reason distance, time, errors and access are separate results. One is not reported in place of another. A layout that removes necessary inspections is not doing the same job, even if it looks faster. The comparison must be set up on the same finished product and the same acceptance limit.

A mockup reduces uncertainty; it does not reproduce all effects of real production. A cardboard part may not represent the mass, temperature or surface friction of the real part. A demonstration without energy cannot verify the magnitude of a pinch risk in real operation. These limits do not make the trial worthless; they explain which question it answers. In the first trial the access geometry can be eliminated, and in the next safe trial the real load and inspection can be tested. The worker is not asked to force a motion under a risky condition. The design is changed, suitable protection is set up, and the next stage is entered only once a safe test condition exists.

There are also learning and order effects in the measurements. If the first layout is always measured on the first trial and the last layout always after the worker has become accustomed, the whole difference cannot be attributed to the layout. For this reason the comparison order is balanced, familiarization trials are separated from the measurement series and the worker code is recorded. Choosing only the fastest cycle is not evidence of a stable method. The distribution, errors and reasons for stopping are kept. In this lesson one safe candidate will be chosen among three mockup layouts, but this choice will not count as a production approval that has passed the pilot gate. The next lesson will look for capacity, quality and safety evidence together in a pilot with higher representativeness.

Formula