Next step is the prediction of the Manufacturing Part Quality, Buidling Time, Cost or Carbon Footprint. This is done based on the Bill of Materials (BoM) and the Technical Product Documentation as starting point. Based on the principle that every process used to build the product is coupled to a part in the BoM a mflow or process Flow is automaticly generated. Adding information of part and process failure rates, test slip, rework are used for a quantitive Manufacturing Part Quality prediction. For building time and cost prediction the part cost, process NRE, process setup time, manual labor time, machine time, hourly rates are added to the parts and processes. Carbon footprint requires not only the part contributions but also the material used and energy. Based on those additions to the mflow a Value Stream Map is created.
Based on the calculation for each part and process in the Value Stream Map the accumulated results of the Manufacturing Part Quality, Building Time, Lead Time, Cost and Carbon Footprint are made visible.
The Value Stream Map highlights the results. The difference with most Value Stream Maps is that the result is a educated guess of the parameters. The method used instead is calculated and based on the TopX position a color is assigned accordingly to one or more of the parameters. By large designs the Value Stream Map can hold thousends of part and processes which makes it difficulat to find the big contributors. Therefore for each item a TopX is created to have a fast start for the mitigation.
Bill of Material (BoM)
The Bill of marterial (BoM) is the starting point of the prediction. A BoM consist out of 3 types of parts which have a different behavior in this method.
- Vendor Parts
- Manufactured Parts
- Assembled Parts
Vendor Parts
Vendor parts are parts which are bought and are not manufactured or assembled by the product manufacturer. As a result the part quality and cost is what you buy. A method for determining the frequency of failures is using the performance of this product from the past or ask the manufacturer of this product for its failure frequency. The unit of measurement is either in % or ppm or DPMO. The processes coupled to a vendor part are assembly processes. The assembly process(es) consist always of a placement process and sometimes a connection process. Cost is determined by the part supplier and as such a fixed value.
Vendor parts have only assembly process accociated to the part.
Examples:
Bolts, screws, nuts:
- Placement process and a tightening process.
- Failure frequency is based on the class bought.
Electronic parts (resistors, capacitors, inductors, active parts, …)
- Placement process and soldering process.
- Failure frequency based on manufacturer performance.
Cost, time and carbon footprint are following the same method.
Manufactured parts
Manufactured parts are made out of one material and undergo a set of manufacturing processes followed by the assembly process(es). Manufacturer processes are milling, drilling, deburring, surface treatments, threading, … Assembly process(es) follow the same structure as for the vendor parts. Here the manufactured part quality is based on the capability of the manufacturing processes. This can be measured in Cpk, Ppk, ppm, DPMO, …. The methods used works with DPMO so a Cpk or Ppk must be translated to a DPMO value.
Assembled parts
Assembled parts follow the same flow as the manufactured parts with as difference that the manufacturing processes are now testing, adjusting, cleaning, .. Part quality now is the contributions of all processes and parts which are used for the assembled part.
Predicted Manufacturing Part Quality, Build Time, Cost and Carbon Footprint
As a result of the value Stream map the Manufacturing Part Quality, Build Time, Cost and Carbon Footprint are predicted. When one or more of the outputs exceeds the specified values a mitigation must be started. To make this easy the Topx for Manufacturing Part Quality, Building Time, Cost and Carbon Footprint are presented together with the lead time path.
The order in which the parts and processes occurs are mostly different. Mitigation of the manufacturing Part Quality will lower the risk of failures but also cost, time and Carbon footprint. To reduce time,cost or carbon footprint seperate actions are common and luckely sometimes an item will be found in the other Topx.