OVERVIEW

The overall picture of the machine acceptance process is shown in Figure 16.1. The process of machine acceptance is a three-phase process. This chapter specifically will attempt to clarify the sequence of events that a customer may go through when accepting a machine and what tools should be used in the process. The process begins with the requirement matrix (unique for every machine and customer) that the customer gives to the supplier, expecting the machine to be built accordingly . (This requirement is discussed in Volume VI.)

This is followed by a check before leaving the plant and is concluded with a check at the customer's plant. A typical checklist before leaving the plant is identified in Table 16.1.

Table 16.1: Machine Acceptance Checklist (before leaving the plant)

Supplier/Team	Yes	No	Action Required
Does the supplier achieve at least 80 points of the supplier grade sheet?	____	____	___________
Are there gages available to measure the characteristics that are critical?	____	____	___________
Have repeatability and reproducibility studies been performed using these gages?	____	____	___________
Is the measurement precision at least 1/10 the specification tolerance?	____	____	___________
Have all measuring devices been calibrated?	____	____	___________
Have provisions been made to measure a range of 30 to 120 parts ?	____	____	___________

A supplier grade sheet is a summary sheet with the minimum requirements that gives the customer and supplier an opportunity to see the progress of the machine as it is built. It is usually a numerical scale of performance and quite often is based on a 100-point scale so that it is easily converted to a percentage. A typical grade sheet may cover the following minimum requirements:

A "PPS" study with a minimum of 30/300 parts; Xbar and R chart showing control	35
Histogram of data and raw data; with a calculated Cpk > 1.33	5
Defined warm-up period (in cycle counts)	15
Documented optimal machine setup guide	10
Gages for critical characteristics (with associated R&R's)	5
Machine setup with cycle times comparable to production needs	15
Cause and effect relationships for product variability (fish bone diagram)	15

This is not an exhaustive list, but it shows that there is a concern about capability of the machine and about whether stability and control have been established. There is nothing that prohibits the customer from extending the list with more requirements. After all, the customer pays the bill! (For example, in the automotive industry usually in Phase I 75 samples are tested , in Phase II 125, and in Phase III 300 samples are required.)

Because we already have talked about capability at length, we will approach the topic of process potential capability on a cursory basis. The details may be found in Chapters 12, 14, and 15.