In Reply to: Routing Time Standards posted by Daniel Dorst on 01/23/00 at 9:55 PM:
: I am currently working in an electronics circuit board plant that is having difficulty in collecting actual time standards for their manufacturing process. Can anyone out there describe to me what they are doing to collect actual time standards? We are in a cost competitive market, and having VERY accurate time standards is a must. I'm looking to compile a best practice study, and post it on the web.
January 31, 2000
I am not aware of anyone that is working on VERY ACCURATE time standards - primarily because there are so many variables in play on any given day in a board shop. That said, I would do the following:
1. For each of the significant unit operations (tooling, IL Fab, Drill, Lamination etc.) declare it's control boundaries - when it starts, when it stops AND where queue time and WIP are allocated. Also make sure that travel time between operations is accounted for.
2. Separate your product mix into appropriate categories for EACH unit operation (i.e. for IL fab the number of cores in a part, for drill the number of drilled holes by bit size, for OL Image Transfer the lines and spaces and annular ring, for plating the aspect ratio and plated area - to name just a few). Each category must affect the time it takes to set-up, process and verify the quality of product produced - don't forget the impact of lab analysis in the wet processes.
3. Calculate an average cycle time for each unit operation AND each category (a large matrix!) that accounts for equipment uptime, an adequate number of operators on each shift, availability of materials and WIP levels allowed.
4. Then add or subtract a "TOC" factor that accounts for the performance of your bottleneck operation including it's buffer as well as how the shop is loaded in relationship to the bottleneck (this will affect the queue time and wip in all of the other operations)
5. Track daily performance (cycle time, wip and thruput) in each unit operation and by each category to verify the model. Adjust the model based on constraints identified by the operators (paperwork, training levels, lab analysis, process control, maintenance routines and engineering intervention for yield improvement etc.)
Please send me the results of your benchmark or the URL of where it will be posted on the web. If you would like help developing and deploying the process above send me an email.