Demonstration appliance for Attributive Inspection

Demonstration of distributions and control charts for attributes

Control charts for attributes are used in a lot SPC-systems. It's important that everyone from top to bottom feels comfortable with these cards. What do we measure, what can we deduce and what can't we? Which is the kind of distribition we are dealing with and what is its influence on our samples? This series of appliances is ideal to demonstrate the control charts for attributes and the distributions (both binomial and Poisson).

How it works

The idea is to simulate a party with a known percentage of defects. What we need is a box filled with small coloured balls. The black ones symbolize the good products, the other colours the products with defects (depending on the colour several defects can be imagined and adapted to the own products). With a scoop one can take a sample out of this box.

There are 3 models:

• Model DAK 1000-1
  1000 balls: 90% black, 10% red
  1 scoop for 25 balls
• Model DAK 1500-2
  1500 balls: 84% black, 10% yellow, 5% blue, 1% red
  2 scoops for resp. 25 and 50 balls
• Model DAK 3000-3
  3000 balls: 69% black, 15% white, 10% yellow, 5% blue, 1% red
  3 scoops for resp. 25, 50 and 100 balls

Advantages

• Cheap technique to explain distributions
• Possibility to experiment without producing one single product
• Simple illustration of control charts for attributes (p, c and u-cards)

Prices

• model DAK 1000-1: 45 EUR
  extra cost for plexi scoops: 10 EUR
• model DAK 1500-2: 60 EUR
  extra cost for plexi scoops: 20 EUR
• model DAK 3000-3: 105 EUR
  extra cost for plexi scoops: 30 EUR