3D PRODUCTION SYSTEMS

MANUFACTURING TOOLS

Time Required Cost Skill Level

By Wayne Meyers, Stratasys, Inc.

 

OVERVIEW

 

Manufacturing engineering’s daily challenge is to maximize production quantities while maintaining

quality and managing costs. To keep operations at their peak, it relies on manufacturing tools that

include jigs, fixtures, templates and gauges.

 

The applications for manufacturing tools range from machining operations to fi nal inspection.

They are used to align, assemble, clamp, hold, test and calibrate components and sub-assemblies

(figure 1). Some are simple in form and easy to construct while others have sophisticated designs

that are difficult to produce.

 

Manufacturing tools are commonly machined or fabricated from metal, wood or plastic. Like

the items that they are used to produce, these tools go through the design, documentation and

production process. For an elaborate or intricate tool, there may be a prototyping, evaluation

and design iteration cycle to produce a jig or fixture that performs as needed. On average,

production of a manufacturing tool takes one to four weeks.

 

Throughout the manufacturing operation, manufacturing tools are common, and yet, they are

virtually transparent when production is running smoothly. However, when problems arise, their

role becomes obvious. To avoid production halts or product defects, immediate solutions are

needed and new manufacturing tools must be quickly designed, manufactured and deployed.

However, the lead time can prove to be a barrier. So, manufacturing engineering may have to

resort to short-term, stop-gap repairs.

 

FDM FOR MANUFACTURING TOOLS

 

Fortus 3D Production Systems with FDM (fused deposition modeling) technology provide

manufacturing engineering a fast and easy alternative for production of manufacturing tools.

Using FDM for direct digital manufacturing (DDM), new tools can be put into service just hours

after the design is complete (figure 2). FDM also offers the advantages of design optimization,

labor reduction and cost reduction.

 

In contrast to machined manufacturing tools, the FDM process requires fewer steps, fewer

resources and less effort on the part of manufacturing engineering. With direct access to a

Fortus system, the engineer converts the digital design into a production tool. There is no need

for detailed engineering drawings (figure 3), requests for quote, negotiations with the internal

machine shop or oversight of a supplier. The self-serve nature of the work flow makes the

manufacturing engineer more productive and allows immediate response to problems on the

production fl oor.

 

The manufacturing tools that are produced with FDM are free of design constraints imposed by

traditional manufacturing methods. This promotes better designs that address the functional

needs and ergonomic requirements of the manufacturing, assembly and inspection processes.

Made from tough and durable thermoplastics, the FDM tools will withstand the abuse of the

manufacturing environment. And when it is time to replace a worn or damaged manufacturing

tool, simply call up the digital data and manufacture another one in only a few hours.

 

PROCESS

 

There are no process modifications required when producing manufacturing tools with FDM. It

can be a simple substitution for traditional manufacturing methods. The only requirement is that

the jig, fixture, template or gauge is designed in 3D CAD so that an STL file is available.

 

To maximize the performance and efficiency of a manufacturing tool, consider capitalizing on

the freedom of design that FDM offers. The additive fabrication process eliminates constraints

 

TOOLS AND EQUIPMENT:

 

- Materialise RapidFit software

- Modular fi xturing system

Figure 1: Assembly is one of many

applications for fixtures. Show here is

an FDM fixture supporting an electro-

mechanical sub-assembly.

Figure 2: A roller arm fixture assists in

assembly. Versus CNC and FDM, there

was a 94 percent cost reduction when

made with FDM:

 

Estimate using CNC method:

Cost $2,300

Delivery 3 - 6 weeks

 

Estimate using FDM system

Cost $300

Delivery 1 - 2 days

 

Figure 3: FDM eliminates the time-

consuming process of detailing

engineering prints (top). Instead,

a simple work instruction diagram

(bottom) can be used.

REAL APPLICATION


 

imposed by machining and fabrication. This allows manufacturing engineering to design a

manufacturing tool with fewer parts, reduced weight and better balance.

 

DESIGN

 

In CAD, create the 3D design of the manufacturing tool. Where the tool makes contact with

a component or sub-assembly, simply use a Boolean subtraction to create perfectly mated

surfaces. Then, offset the surface slightly to avoid interference.

 

An alternative to manually designing fixture components is Magics RapidFit, a software module

from Materialise. RapidFit, which is discussed in the “Manufacturing Tools: Modular Fixtures”

application guide, automatically creates contact elements from the CAD data of the part that

is held by the tool. This guide also details the construction of modular fixturing systems (fi gure

4), which are ideal for single- or intermittent-use applications.

 

If the manufacturing tool has tight tolerance specifications, add machine stock to the critical

areas. After construction in the Fortus system, the tool can be milled to design specifi cations.

 

When designing a manufacturing tool that is made with FDM, try to break free of old design

practices. Instead of designing to satisfy the constraints of the milling, turning or fabrication

process, focus all efforts on designing the tool for the best performance. Make it as complex

and intricate as it needs to be rather than trying to simplify the design to make it practical.

Since FDM is an additive fabrication technology, design complexity will have no impact on time

or cost.

 

Following are some design tips to assist in breaking from design traditions:

 

Reduce Weight:

 

A manufacturing tool constructed from a Fortus plastic will be lighter than a comparable tool

made of metal or wood. However, further weight reductions are possible. Since the addition

of features does not drive up manufacturing time or cost, remove material from the tool by

adding pockets, channels and holes. Eliminating excess material will reduce worker fatigue

when using a handheld assembly tool. For larger, stationery tools, the weight reduction will

make it easier to move. In either case, reducing the material in the manufacturing tool will

reduce FDM build time and cost.

 

Consolidate Parts:

 

Manufacturing tools are often constructed in pieces to allow them to be machined or

fabricated. This is unnecessary for an FDM tool. Instead, consolidate all pieces of the tool into

a single part. Part consolidation has many benefits. It will eliminate assembly of the tool, which

decreases labor and time, while eliminating interference issues and improving accuracy. Single-

piece construction also simplifies tool room operations as there are fewer items to inventory,

maintain and track.

 

Design for Function:

 

Due to the limitations of fabrication and machining, manufacturing tools would have very

linear designs with geometric shapes. This is no longer necessary. FDM encourages designs

with freeform shapes and flowing lines (figure 5) that can improve the performance of the

manufacturing tool. It also promotes ergonomic designs that improve the productivity of line

workers.

 

Iterate the Design:

 

The first design does not have to be the final design. The initial version of a sophisticated

manufacturing tool can serve as a functional prototype or bridge-to-production solution. Since

there is little delay and minimal labor required to make subsequent tools, gather performance

data from the first iteration; make design a revision; and produce a better manufacturing tool.

Following the design of the ideal manufacturing tool, export an STL file and import that data

into Insight build preparation software. Standard build parameters may be used. However, for

large or bulky items, consider using sparse fi ll (figure 6) or double dense sparse fill. This build

technique will reduce the volume of material within the part, which reduces weight, build time

 

and cost.

 

MATERIAL SELECTION

 

All Fortus materials can be used when producing manufacturing tools (figure 7). For material

selection, the primary factors will be the suitability to the mechanical and thermal conditions

under which the manufacturing tool will operate. For example, if strength and rigidity are

required, PC or PC-ABS may be ideal for the application. If temperature and chemical

resistance are needed, PPSF may be the better choice.

 

Figure 4: Modular fixturing systems are

ideal for intermittent use. Pictured is

an FDM-made modular system (white)

used to support a gas tank while being

bonded.

PAGE 2

Figure 5: FDM manufacturing tools can

have complex designs without driving

up time or cost.

Figure 6: To reduce weight, build time

and cost, consider sparse fill for thick-

walled parts.

Figure 7: All FDM materials are suitable

for manufacturing tools. Pictured is an

ABS fixture for mounting a heat shield.


 

For complex and intricate manufacturing tools, consider using one of the ABS materials, including

the PC-ABS blend, so that soluble supports can be used. The soluble supports will reduce direct

labor and ensure that support material is completely removed, even from inaccessible features.

 

PRODUCTION

 

Producing manufacturing tools requires no special consideration. Prepare the STL file and build

the tool in the same way as any model or part.

 

Following the build, the part is taken off of the Fortus system, and the support structures are

removed. In most applications, no other finishing work is required. The manufacturing tool is ready

to be deployed to the manufacturing fl oor (fi gure 8).

 

DIGITAL WAREHOUSING

 

If a manufacturing tool is damaged or lost, it can be replaced quickly and with little effort. Simply

access the tool’s design data in CAD, export an STL file and rebuild the jig, fixture or gauge.

 

Because replacement and duplication is so efficient, consider digital warehousing for

manufacturing tools that are used infrequently. Instead of carrying an inventory in the tool

room, dispose of the tool between uses and rebuild when needed. This new practice will

eliminate warehousing issues such as spending an inordinate amount of time searching for the

manufacturing tool.

 

CONCLUSION

 

Manufacturing tools are vital for the productivity of the manufacturing process and the quality of

the products. Replacing machining and fabrication with FDM makes production of these tools a

simple, flexible, affordable and fast process. Instead of waiting weeks for a manufacturing tool, it

can be ready in a few hours, often with a cost reduction of 50 to 75 percent.

 

With FDM, the manufacturing tools are constructed faster and made better. The short lead

time allows iteration of a tool’s design. Combined with the freedom of design, manufacturing

engineering can create manufacturing tools that are optimized for performance and

ease-of-use.

 

Manufacturing engineers tend to gravitate to FDM when given access to the technology. It

eliminates steps in the process, reduces dependency on others, expedites delivery and increases

productivity. In many cases, this leads to more manufacturing tools on the manufacturing fl oor,

which increases production quantities, product quality and fi nancial gain.

 

For more information about Fortus systems, materials and applications, call 888.480.3548 or visit www.fortus.com

 

PAGE 3

Figure 8: After removing supports,

manufacturing tools are ready for use.

Cost estimate of part pictured:

 

Estimate via traditional method:

 

Cost: $3,000 - $4,000

Delivery 2 - 6 weeks

 

Estimate using FDM:

Cost: $600

Delivery 1 - 2 days

 

FDM PROCESS DESCRIPTION

 

Fortus 3D Production Systems

are based on patented Stratasys

FDM (Fused Deposition

Modeling) technology. FDM is

the industry’s leading Additive

Fabrication technology, and the

only one that uses production

grade thermoplastic materials

to build the most durable parts

direct from 3D data. Fortus

systems use the widest range

of advanced materials and

mechanical properties so your

parts can endure high heat,

caustic chemicals, sterilization,

high impact applications.

 

The FDM process dispenses two

materials—one material to build

the part and another material for

a disposable support structure.

The material is supplied from a

roll of plastic filament on a spool.

To produce a part, the fi lament

is fed into an extrusion head and

heated to a semi-liquid state. The

head then extrudes the material

and deposits it in layers as fi ne as

 

0.005 inch (0.127 mm) thick.

Unlike some Additive Fabrication

processes, Fortus systems with

FDM technology require no

special facilities or ventilation

and involve no harmful chemicals

and by-products.