Fixturing Outline

• Understanding Lean

• Concepts

• Foundation Systems

• Vise Fixturing

• Magnetic Fixturing

• Vacuum Fixturing

• Modular Fixturing

What’s wrong with this picture?

Interchangeable parts

“Systeme Gribeauval”

In the late 18th century, French General Jean Baptiste Vaquette de Gribeauval suggested that muskets could be manufactured faster and more economically if they were made from interchangeable parts

In 1818 Eli Whitney built his first milling machine which precisely

shaped metal parts.

His efficient methods, especially the use of interchangeable parts, revolutionized the small-arms industry, and gradually these production methods were applied to most types of manufacturing.

The Knee Mill

• In 1862 Joseph Brown, later of Browne & Sharpe, began development of the fist “Universal Milling Machine”.

• “in order to insure firmness in the said carriage it is mounted upon a heavy knee”

The continuing problem

• “…that many frequently desired machining operations have heretofore been impossible, or at best have required changing the set up of the work on it’s support table, an operation which greatly slows up production and increases the likelihood of inaccuracy in the finished work.” April 4, 1939

US Patent 2,275,291

MACHINE TOOL OPERATING AT UNIVERSAL ANGLES IN ALL LOCATIONS

Muda (waste)

• The table of the machine has not undergone any significant changes in 70 years.

• "The most dangerous kind of waste is the waste we do not recognize." - Shigeo Shingo

Lean Terms• ▪Just In Time (ジャストインタイム ) (JIT)• ▪Jidoka (自働化 ) (English: Autonomation - automation with human

intelligence)• ▪Heijunka (平準化 ) (English: Production Smoothing)• ▪Kaizen (改善 ) (English: Continuous Improvement)• ▪Poka-yoke (ポカヨケ ) (English: fail-safing - to avoid (yokeru)

inadvertent errors (poka))• ▪Kanban (看板 , also かんばん ) (English: Sign, Index Card)• ▪Andon (アンドン ) (English: Signboard)• ▪Muri (無理 ) (English: Overburden)• ▪Mura ( 斑 or ムラ ) (English: Unevenness)• ▪Muda (無駄 , also ムダ ) (English: Waste)• ▪Genchi Genbutsu (現地現物 ) (English: Go and see for yourself)• ▪Manufacturing supermarket where all components are available to be

withdrawn by a process

Mura (unevenness)

The last bottleneck

• Implementing LEAN in a milling department bottlenecks at 80-85% spindle optimization due to set up and changover

• Different shops have different needs

• Some may need vises

• Some may need round chucks

• Some may need a manual magnet

Some may need electo-perm magnetic fixuturing

• Some may need vacuum

• No single workholding manufacturer can meet all of the needs of every shop

• No single builder has offered an alternative solution

• The problem is that a t-slot has been the most versatile way to mount workholding because there has been no development of a “standard” for workholding…

So, how can you maximize your facilities throughput?...

"Where there is no Standard there can be no Kaizen"

- Taiichi Ohno

Iron Planer, circa 1825

Photo courtesy: American Precision Museum

• Most shops have about a 12-15% spindle optimization rate: They only cut 12-15% of working hours.

• If you implement lean processes, standardize your cutting tools, optimize your job routing you will still only reach 80-85% spindle optimization

• Take a walk through your facility now and see how many green lights are on….

Spindle OptimizationHow often are your machines making you money?

What percentage of the day are your machines actually CUTTING MATERIAL?

Workholding 101

Genchi Genbutsu:

Go and see for yourself!

•What are your part sizes?•Can you group them in Families?

It's only the last turn of a bolt that tightens it - the rest is just movement. ~ Shigeo Shingo

Workholding 101

•What is your lot size?

Vertical Envelope

• What Size is the machine envelope for your Verticals?

Horizontal Envelope

• What Size is your machine envelope for your horizontal?

Efficient use of the table?

• Is the table space maximized?

• How long to change to a new set up?

This eliminates changeover

•Two double vises•Indexer

•Multiple parts can be run

•But is this the best solution?

•What if the indexer is only used for a short run job once a month?

Is this a good solution?

• Is the table space maximized?

• How long to change over to another fixture set up?

Foundation Systems

Jergen’s Ball Lock™

Jergen’s Ball Locks

Foundation Systems

• Modern Industries SpeedLock

• Speedlock Recievers can replace the need for t-slots

• Eliminating t-slots increases Z axis travel: no stacking of fixtures

• Eliminating t-slots reduces the overall weight on the ways of the machine: Longer way life & less inertia in motion

How it works

• Now you can Mount:

•Speedloc in a standard configuration for increased versatility with reduced set up and changover time.

Vises

• In 1964 Kurt introduced the AngleLock

• Addresses the major problem of part deflection

Most All Vises Force parts down to the bed

• For every pound of forward force there is 1/2 pound of downward force

• Pushes the part into the bed of the vise

Single Station Applications

Single Station Design

• Designed for a manual milling machine in the 1960’s

• Good use of work envelope

Is this efficient?

• Once a standard fixturing method is put into your shop it will expand more and more.

• But is it the best “evolution”?

Many shops start with a single station vise and then they grow to fill the table….but fail to utilize the entire work envelope

Is this more efficient?

•More of the available machining envelope is utilized…

•But, what about changeover when a large plate job comes in….. A 4th axis job?

Now can you tell what’s wrong with this picture?

Vise Fixturing

Vises are the most versatile type of fixturing in your shop

There are a number of manufacturer’s of CNC vises

Why Double vises

Double vises are essentially large envelope single station vises and provide a higher level of shop level versatility

Maximize table space

Depending on the double vise manufacturer double vises can be ganged next to each other and mounted to a pallet for quick changeover

Interchangable Jaws

• Outside jaws can index

• Center jaw “flips” for two part applications

Modular Vises

"Low Profile Design" for added tool clearance.Available in 2" Grid Pattern Spacing.Uses STANDARD 6" wide jaw mounting on fixed and moveable jaws.Ideal for specialized applications

Soft Brick vises are a very economical solution

• Stevens Soft-Brick Vise eliminates the need for changing jaws on soft jaw vises. • The vise needs no soft jaws because the vise itself is a soft jaw. • Made from 6061 aluminum, the low-cost vise can be machined by users with cavities to fit specific workpieces.

5 Axis machines require 5 Axis Fixtures

With the advent of Mill-Turn machines and tighter tolerance work a new type of fixturing is being required

Vises & Dovetail fixtures

•Once Again there are 5-Axis self centering vise solution and modular “dovetail” solutions for holding parts that require access to 5 of the 6 sides of a part

A variety of Vise Solutions are available

Magnetic Terms• Magnetomotive Force -- The quantity of magnetic field force, or "push."

Analogous to electric voltage (electromotive force).

• Field Flux -- The quantity of total field effect, or "substance" of the field. Analogous to electric current.

• Field Intensity -- The amount of field force (mmf) distributed over the length of the electromagnet. Sometimes referred to as Magnetizing Force.

• Flux Density -- The amount of magnetic field flux concentrated in a given area.

• Reluctance -- The opposition to magnetic field flux through a given volume of space or material. Analogous to electrical resistance.

• Permeability -- The specific measure of a material's acceptance of magnetic flux, analogous to the specific resistance of a conductive material (ρ), except inverse (greater permeability means easier passage of magnetic flux, whereas greater specific resistance means more difficult passage of electric current).

Magnets

• North and South remain the same no matter the size

Flux Lines

• The philosopher-scientist Rene Descartes noted that this invisible "field" could be mapped by placing a magnet underneath a flat piece of cloth or wood and sprinkling iron filings on top.

• The filings will align themselves with the magnetic field, "mapping" its shape.

• The result shows how the field continues unbroken from one pole of a magnet to the other

Magnetic Fixturing

• Understanding magnetic flux lines

• Thicker is good• Thin is bad• Bigger is good• Small is Bad.

Manual Mag Application

Magnetic on HMC

• Permits all five sides to be machined

Mag Applications

• Large Plate applications

• Can fixture across multiple vises

• Machine 1018 jaws on top to tram in Z flatness

How Electoperms work

• Electromagnetic chucks feature a combination of reversible magnets (blue) on the base of each magnetic poles +  "power" magnets (red), surrounding the poles (yellow).

• This structure generates a working surface creating a multiple magnetic stitching, thus granting a perfect clamping of any workpiece.

• The double reversible magnet characteristic allows the Electomag chuck to move the internal magnetic field outside, thus activating the working surface.

DeMag Phase

During the DEMAG phase the magnetic flux is short-circuited inside the chuck.No residual magnetism is present on the chuck surface.Zero power consumption.

MAG Phase

• During the MAG phase the chuck will keep the workpiece safely clamped for an indefinite period of time with 100% strength.Zero power consumption.

ElectoPerm Magents

• Each 50mm Square pole has 2 tons of holding force

• Fixed poles and adjustable poles

Magnetic & Cutting Tools

Part thickness

• Minimum thickness is 1/2”

• Minimum DIAMETER is 8” to maintain coverage of 50mm poles

Holding warped parts

• Adjustable poles compensate for uneven parts by connecting and completing the magnetic circuit

Understanding limitations

• Note where the flux line connects the poles

• Note the 50 mm distance and the peak of the flux line

Through Holes

• Chips do not “stick” to the part

• Chips are TOO THIN

Vacuum Fixturing

• Most companies using Vacuum fixtures create a grid or custom fixture

• If you “break through” the part you lose vacuum pressure

Vacuum Fixturing

• There are alternatives:

• The VAC-MATTM System uses a series of suction cups

• “Breaking Through” does not present as significant of a problem

Vacuum Fixturing

• For VERY THIN parts you can use a sintered metal/ceramic vacuum chuck

• These chucks are made of a semi-porous material that allows you to hold thin parts

Now, What’s wrong with this picture?

For questions:

Bernard T. MartinRapid Production Marketing232 Dogwood CircleBaden, PA 15005-2346m: 412.996.5700bernie@rpmconsultants.uswww.rpmconsultants.us