I am trying to help out a friend (while holding onto my day job). His employer is suffering huge losses due to scrap, and mis-co-ordination due to the size and complexity of its manufacturing process. He thinks I can design him a custom system from scratch, but his problem is so general and ubiquitous that I'm sure it's been solved many times in the past. I'm trying to save him the expense that engineerng hours cost by locating as much of the system as possible in a pre-manufactured form, and minimum price.
When an order comes in for a specific lot size of a specific final good, the facility starts with raw material, which must be cut, machined, polished, and drilled to tight tolerances at multiple workstations, each feeding the next. A lot starts with a certain amount of overage, to allow for scrap along the way, which can happen at any stage. Some types of damage can be repaired in another stage. Other damaged goods may be recycled in a smaller product, and some must be scrapped.
The chief economic consequence is when remaining semi-finished material falls below the minimum order size in the middle of the process, but the shortfall is not discovered until time of shipment. This begets a make-up order that effectively doubles the production time, leading to unhappy customers.
The employer has tried attaching traveller documents to each lot of material, requiring employees to fill out forms at the beginning & end of their processing steps, but the documents often become separated from their material and are lost. There is no central process monitoring system to catch these shortfalls automatically as soon as they occur, and not means to compile statistics that would identify specific stages/employees/products with the majority of the problems.
My friend wants a bar code scanner and numeric keypad at each workstation, with separate bar codes for each job, workstation, and employee, and a centralized data base management system that is user-friendly enough to allow process monitoring as something less than a full-time job necessitating hiring quality-only employees.
I would estimate the number of stages or workstations at around 12, losses at $4k/month, and total employees at 60. We will have to run the cable for the network ourselves so that is open at this point. I hope to keep the hardware costs under $20k, but this is a guess.
The users would input quantity in & out, times in & out, start & stop times of the stage, and workstation & employee numbers. For output I can see a list of all jobs in progress, and the ability to pull up a graph of the projected final item count vs time, with markings to tell what step is represented by each bar.
As the customer becomes more acquainted with the system's capability, he would want to be able to: - Identify bottlenecks that jam up the pipe, - Compare productivity of different employees or machines, or shifts, etc.
The environment holds a lot of dust, but no grease or oil. It's all within one building, which has a high, open ceiling, which is probably where we'll run the cable/wiring.
Can anyone point me at a framework involving a central PC + (relatively inexpensive) input stations + network that can tackle this situation with a little configuration work and leave the employer with a with a system he can maintain without a full-time network professional to keep it going?
Is there an industry-standard term for this kind of system?
I once worked for an environmental monitoring manufacturer, who built simple input stations around (Intel) 8096-family MCUs, linked together by a proprietary protocol based on DTMF tones. The bandwidth was miserable, but the data was not excessive, and it would work over really cheap wiring (UTP).
I need to make a proposal in the next month or so.
Thanks in advance for your input. ============================================================ Gary Lynch | To send mail, change my bookworm@no$pam.com | domain name from "no$pam" | to "execpc". ============================================================