Newsletter November 2009

In this issue:

 

• Waste not, want not. 7 Deadly Wastes Revealed.

• Text & Logo Design Considerations

• The Plastic Parts Gold Standard: ABS

• Tips & Tricks for converting Autodesk Revit files for 3D printing.

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Waste not, want not. 7 Deadly Wastes Revealed.

1. Over production

2. Inventory

3. Transportation

4. Defects

5. Over processing

6. Waiting

7. Environmental

Fall is a great time to think about the impact your manufacturing plant has on the environment.

Over production. Over production occurs when raw materials and energy are consumed in unnecessary production. For example: food, beverage and medical device manufacturers produce goods which have expiration and/or obsolescence dates. For these manufacturers, producing only those products which will be consumed or used is very important. Why? Having to dispose of products that could not be used before expiration is over production. Another type of over production is using extra hazardous materials which cause extra emissions, waste disposal, and employee exposure.

Inventory. Too much of a good thing is not always better, as is the case with inventory. The more you have to store, the more square footage you need to heat, cool and light. Also, more materials are used to replace damaged products.

Transportation. If you’ve ever been behind a diesel truck in rush hour traffic this concept will be especially clear. Additional transportation of goods means more emissions (cough, cough), more fuel (energy) used, more packaging used to protect goods during shipment and the fact that you’ll have to reproduce products that are damaged during shipment. To add insult to injury, transporting hazardous materials requires special shipping and packaging.

Defects. Anytime you have to reproduce your product, you spend energy and deplete raw materials. Also, defective products may require recycling or disposal. Lastly, you’ll need to carve out a footprint on your factory floor for people to rework or repair the defective product increasing energy spent on heating, air conditioning and lighting. 

Over processing. This one is really simple. You’ll use more energy if you have to operate equipment related to unnecessary processing. You’ll also add more parts and raw materials per unit produced. Anytime you do too much of anything, energy and wastes are increased. Some manufacturers strive to right size equipment to reduce energy used per unit produced.

Waiting. Downtime is never good because it’s always costly. Most manufacturers can easily see the production loss aspect, but some do not yet see the environmental impact. If your production floor is waiting for parts, equipment or direction it’s possible to have materials spoil or components damaged. All the while, the equipment is running and the lights are still on.

Environmental. Energy consumption is king; however, there are a lot of other factors to consider. Think about the excess materials and resources you have on hand. Scrap product contributes a great deal to the environment because it is all primarily waste. Finally, consider the hazardous materials you use to manufacture your product and research environmentally friendly alternatives.

If you didn't catch last month's topic on how RedEye's digital manufacturing technology is eco-friendly, click here. Now that you know the 7 deadly wastes, review our services to see how RedEye can help save you time, cut costs, reduce over production, inventory, defects, waiting and over processing. 

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Text & Logo Design Considerations

The text shown in the above examples are a good representation of optimal font size, type of font and spacing. Actual Size (2”x4”)

Text and logo's are commonly incorporated into new product design for many reasons, but primarily for product identification or brand recognition.

Producing end use parts using CNC or injection molding is common, but what do you do when using Fused Deposition Modeling (FDM)?

Our teams of knowledgeable digital manufacturing professionals note 3 key factors you should consider when designing new products with text: font size, type of font & spacing.

Font size. Text and logo’s follow the same rules as small features. When incorporating raised or embossed text, make sure the height of the text is at least 0.015” high with a cross section of at least 0.015”. Thinner text is difficult to build for the same reason it’s difficult to build thin walls.

Type of font. When possible try to use common fonts, such as: Arial, Tahoma, or Verdana because these fonts have already been designed to print clearly regardless of size.

Spacing. A good rule of thumb for spacing between letters is .020”. This will insure each letter is clearly distinguished amongst the other characters.

When using a service provider to produce end use parts with FDM, it’s a good idea to talk with your project manager about text resolution. RedEye staffs a team of project managers who have produced thousands of end use parts, many that include text, logos and other artwork.

Project Managers have access to a multitude of build properties that you may not. Build properties are determined when STL files are sent to FDM equipment for processing. For example: build orientation directly affects text resolution. If set improperly your letters may look garbled, scratched or have sink marks (depressions) around the outside of the letters.

Hopefully this short segment has made your job a little easier. For more information about how to create smooth, accurate, STL files, download our Guide to Quality STL Files.

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The Plastic Parts Gold Standard: ABS (Acrylonitrile/ Butadiene/ Styrene)

A guitar produced with ABS features the variety of colors available at RedEye.

ABS (Acrylonitrile/ Butadiene/ Styrene)
If you used your telephone today, you touched an ABS part. The first ABS plastics, patented in 1948, were mechanical blends most often used in pipe fittings; however, they were vastly different from the processor-friendly materials of today.

What’s important for you to know today is that ABS is a good material for both prototyping and end use part production (digital manufacturing) because it provides good impact strength and stiffness. This is especially true when compared to lower cost resins used in SLA or SLS prototyping processes.

Many manufacturers and engineers choose ABS because it is an amorphous thermoplastic known for its rigidity, dimensional stability, color consistency and availability, lustrous abrasion-resistant surface, and midrange cost. Its defining characteristic is its notched Izod impact strength of 2ft lb/in.

Applications
Because of its well rounded properties, ABS is used in a vast number of applications throughout many industries. If you look around you’ll see lots of ABS parts: appliance and electronics housings, medical instruments, office and household furniture, machine housings, refrigerator liners, luggage, toys, camper bodies, thermoform prototype molds, boat hulls and snowmobile shrouds.

Material Specifications
Material specifications vary not only on the supplier of ABS plastic, but on the process you choose to manufacture your parts. Since we’re most familiar with manufacturing ABS plastic parts via Fused Deposition Modeling (FDM), the specifications below will show you what you can expect when using this process and the type of ABS used at RedEye On Demand.

• Wall Thickness: To produce optimal parts in ABS plastic, you should design wall thicknesses at 0.04 inches (1.016mm).

  • You may produce ABS parts with a minimum wall thickness as low as .015 inch successfully, however; it is geometry dependent.

  • Part thicknesses greater than an inch are easily achievable.

  • You can build very thick, bulky parts that are lightweight, yet rugged by having your parts built with Sparse Fill. The Sparse Fill option gives your part a honey-comb like interior while providing you with the same exterior quality at a reduced cost.

• Radiusing: ABS is not a notch-sensitive material; however, radiusing the corner of an ABS part created via FDM improves its strength by distributing corner stresses over a broader area.

  • Inside corner radiuses should be limited to not less than 25% of the part’s wall thickness.

  • For maximum strength the radius should be 60% of wall thickness. Larger radiuses can be specified, but this will not significantly increase part strength.

  • It's a good idea to apply the same design techniques as you would to injection molded parts; however, the FDM build process allows you the design freedom to create straight non-radiused areas as needed.

• Draft Angles: ABS parts can be created with no draft angle.

  • The FDM build process allows you the design freedom to create the part for its intended application without the worries of how it’s going to be manufactured.

• Cavities & Internal Features: You can create holes, cavities and internal features of almost any size.

  • Uniquely, the FDM build process allows you to build internal features that snake around the inside of the part and virtually any depth.

• Tolerances: ABS is a dimensionally stable amorphous material.

  • Tensile Strength¹: 3,200 psi (22 MPa)

  • Tensile Elongation: 6%

  • Flexural Stress: 6,000 PSO (41 MPa)

  • Izod Impact, notched: 2 ft-lb/in (106.78 J/a)

  • Heat Deflection: 195° F (90° C)

  • Maximum Build Dimensions: 23.6" x 19.7" x 23.6" (larger parts can be built in pieces and bonded together)

  • Accuracy: +/- .005 inch or +/- .0015 inch per inch, whichever is greater (+/- .127mm or +/- .0015mm per mm whichever is greater. Note: Accuracy is geometry dependent.

Download ABS Material Spec Sheet

Get a free copy of our Materials Comparison Chart

¹Tensile strength data is based on ASTM standard D-638

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Tips & Tricks for converting Autodesk Revit files for 3D printing.

Calling all Architects! Do you use Autodesk Revit? If so, take a peek at our Revit Conversion Guide for more information on converting files to STL format - the most common file format required for 3D printing.

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