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FLEXIBLE MANUFACTURING
for Build-to-Order & Mass Customization

Executive Overview

Flexible Manufacturing supports Mass Customization and Build-to-Order by enabling the on-demand manufacture of a variety of parts and products.

For fabricated products, all operations can be performed flexibly without setup delays or extra costs. Here are some examples of flexible part manufacture:

Flexible CNC. All CNC machine tools (even the ones you are using in a batch mode)
are capable of fabricating families of parts. Source of image right: Haas Automation of Oxnard, CA:9AD41E98 https://www.haascnc.com/index.html

Three elements enable this flexibility:

1) Standard raw materials that are supplied spontaneously (see below) so that they are always available to avoid procurement delays.
2) CNC programs can be instantly retrieved or generated “on the fly.”
3) Setup or workholding delays are eliminated with cellular manufacturing cells (next)

For Electronics Products.    These principles also apply to electronics products, since Printed Circuit Boards are also built by CNC machine tools that can place a variety of comments onto versatile “bare boards” (point #1 above) using quickly  loaded programs (point #2) onto standard panels or standard material handling rail widths (point #3).

Cellular Manufacture

Source Cells can cut parts or material “blanks” to-order for fabrication cells or assembly lines.
        The illustration shows a source cell for sheet metal. If raw material can be standardized on one gauge, then the standard gauge can be fed from a coil, for substantial raw material savings. This also results in better nesting of part shapes and avoids the very wasteful practice of trying to cut part shapes out of 4' x 8' sheets and trying to get any more use out of the  remnants  left over.
          Source cells can programmable cut on-demand all the shapes of that gauge for the entire factory, and could even become a supplier for other factories who would appreciate fast delivery of low-volume/high-mix blanks at low-cost with no inventory at their shop or their suppliers'. This would help justify the investment for the roll feeder.

 

The next illustration shows multiple coil or reel feeders that
can feed either of two (or more) standard materials on-demand, without any setup delays,  to multiple work stations in series,
in this case work stations "A," "B," and "C,"

    These drawings are all Copyright © 2018 by David M. Anderson.

 

Flexible Fixtures for Rectangular Parts. For each machine tool, flexible fixtures can be
 concurrently engineered to instantly accept any part or raw material
 “blank” in the part family in any volume, down to one piece; The
illustration shows the flexible fixture principle for milled parts.  Similar
 flexible fixtures can be structured for cylindrical parts for lathes (not shown).

      The illustration at the right shows four flexible fixtures on one milling machine  bed in which each fixtures allows instant positioning and quick clamp down of any part in the families, shown by different sizes in different colors.   All parts in all families can be  positioned quickly against the horizontal "X" datum bar and the vertical "y" datum bar and the machine tool bed, which is e "Z" datum (out of image).  Note that the center of the milling machine bed can still be used for general machining or for other fixtures.

Flexible Lathe Cell for On-Demand Shaft Fabrication fpr axi-symmetrical parts for motors, pistons, etc (see illustration below).

One family criteria would to base the input bar stock on standard shaft diameter and material bar stock, which may result in some products getting a “better” material than they need, but the value of the model would result in a net lower total cost. The ends of shafts would be turned down to each product’s dimensions, which could be pre-determined for a standard size (Build-to-Order) or custom dimension for Mass Customized specials. If the machine tool was a CNC Machining Center  (as shown in the top photo), it could also add a wide range of flats, keyways, grooves, and other features.  Custom features could be  machined in flexible fixtures as shown above..


The bar stock may have automatic feeders and be long enough to minimizing bar changing and remnant waste,  which can also be automated.  Thus, the cell could build any shaft in the family  on-demand
and without any inventory or setup delays or costs.


End Caps. Castings  need an expensive tool for every shape,  plus lengthy setups and inventory for each batch.  Build-to-Order principles would use one versatile standard end cap which could be designed for each family that would include all the cast features (whether used or not).  Custom features could be  machined in flexible fixtures as shown above.  In fact, die cost could be further cut in half if every end cap raw casting could be versatile to be machined into front or back versions.  That obeys the DFM guideline that recommends to "eliminate right and left-hand versions."

Any extra shapes in the raw casting or any extra machining would be paid back several times over by cutting in half the die cost, inventory cost, and extra setup costs.

Cylindrical Housings
. For sheet metal motor housings, a flexible cell could build housings from a standard sheet thickness and grade with diameter and length fabricated on-demand, like the shafts. For cast housings, similar logic applies to minimize the number of dies to the absolute minimum with the a single versatile raw casting as  as with end caps for each family, which would be CNC machined for different functionality.   Custom features could be  machined in flexible fixtures as shown above.

In all cases involving castings, reducing each families casting count to one would allow them to be economically stocked to enable on-demand build-to-order.

Extra Profit Opportunities (See page 295 of the book, "Build-to-Order and Mass Customization."

Mass-customizers can use their versatile design and manufacturing capabilities to offer new, related, value-added products/services that expand the scope of their markets. These offerings may cost little extra to add, especially if they can be done in existing CNC operations. And yet, they may save customers so much time and money that they would gladly pay the mass customizer for the options, especially if these features are difficult for customers to make.

For instance, one of the author’s clients, the Hoffman brand of Pentair (see case study) built a plant in Lexington, Kentucky, which can spontaneously build-to-order a wide variety of standard or mass-customized electrical enclosures. It’s high-profit value-added opportunity is to use the very same CNC laser cutters that make the boxes to make the holes and cut-outs that cost their customers much time and money to do on their own.

 

Spontaneous Supply Chains

Standard parts and materials, mentioned above, can be procured spontaneously without forecasts, inventory, or waiting for ordered parts to arrive, as described at: http://www.build-to-order-consulting.com/supply_chain.htm  and delivered “dock to line” so they are always available at all points of use, instead of the common mass-production practice of sending all parts and materials to the Receiving Department where they are “kitted” into a batch for scheduled batch production runs.
     The article at: http://www.build-to-order-consulting.com/kanban.htm shows automatic resupply techniques such as kanban, steady flows, min/max, and breadtruck (free stock). Two-bin kanbans can range from pairs of cardboard bins to pairs of truck trainers, where one bin or truck trailer is in use and the other is going back to “the source,” which could be a supplier or a manufacturing cell.


The author of this article, Dr. David M. Anderson, can be reached at 805-924-0100 or
 anderson@build-to-order-consulting.com 

He has published dozens of articles that are posted at www.design4manufacturability.com , www.HalfCostProducts.com, and www.build-to-order-consulting.com

Copyright © 2018 by Dr. David M. Anderson, P.E.

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