Abstract - Penn State Mechanical Engineering



IVALO Lighting

ME 597B

Designing Product Families

Submitted to: Dr. Simpson

May 4, 2001

|Dave Ericson |Mike Minnicino |

|Nakhiah Goulbourne |Ryan Noss |

|Andrew Hoskins |Jeremy Schadler |

|Abstract |

|The Ivalo Lighting Incorporated specializes in light fixtures for residential and |

|commercial use. It is desired that a hanging light fixture of Italian design be made. |

|The customizability of the light fixture is to be investigated. For a predetermined |

|design, CAD models and CNC machine prototypes of varying sizes are to be made. This |

|family of products will be created using concepts from scale-based product family |

|design. The models are required for display and design purposes and it is desired that |

|they be inexpensive and durable. |

|[pic] |“Dr. Hakkarainen is the founder of Ivalo Lighting Incorporated, a|

|SUSAN HAKKARAINEN |company that will produce premium decorative light fixtures for |

|President, |the residential and commercial market. Ivalo fixtures use cutting|

|Ivalo Lighting Incorporated |edge technology to produce advanced, high fashion designs that |

| |have superior optical properties and quality while maintaining |

| |ease of installation. Ivalo will feature designs from all over |

| |the world and is starting with Italian designs.”  |

Source: Cornell University - School of Electrical and Computer Engineering

Introduction

Ivalo designs and manufactures lighting fixtures to be used in both residential and commercial environments. Under the guidance of Susan Hakkarainen, president and founder of Ivalo Lighting Incorporated, the Product Families Lighting Team was formed. At the beginning of the project, Ivalo had both a 4-foot prototype and a 4-foot working model of the lighting fixture. Ivalo’s objective for our ME 597b group was to determine how the 4-foot design would scale into 3, 5, and 6-foot designs. The design strategy and manufacturing strategy will be discussed in the subsequent sections followed by a discussion of the relevance of the proposed project with regards to the course question.

|[pic] |[pic] |

|Figure 1. Working model and SLA prototype of Ivalo Lighting's four-foot light |

This objective was difficult to achieve in the time allotted due to limited resources and unfortunate delays in receiving the necessary files. As Ivalo’s four-foot SLA prototype was estimated to have cost $30,000, one of the aspirations was to formulate a plan to manufacture the prototypes quickly and easily. The group’s goals for this project were:

▪ Prototype the 3, 4, 5, and 6 foot lighting fixtures

▪ Make durable prototypes

▪ Create these prototypes in a economically feasible manner

▪ Create prototypes quickly

▪ Create a product platform so that the lighting fixtures can be scaled

Through solid modeling CAD programs, CAM programs, heavy thinking, hard physical labor and long hours, each design was prototyped.

Design Strategy

Once the existing four-foot prototype and corresponding original drawings were obtained from Ivalo Lighting, an original CAD model of a new four-foot light design was generated using a parametric modeling program called IronCAD. After designing the four-foot model that we were to construct, the next step and the source of particular concern was the strategy to be employed when scaling the model. Three different strategies were considered: proportional axis scaling, non-proportional axis scaling, and attribute scaling. Proportional axis scaling, as its name suggests scales proportionally in each direction. Figure 2 shows how the four-foot light may be scaled to generate a smaller three-foot model. Notice how the three-foot looks like simply a smaller version of the original as expected.

|[pic] |[pic] |

| |[pic] |

Figure 2. Proportional Axis Scaling

Non-proportional axis scaling, on the other hand, scales differently in the three axial directions. In this particular case, the scaling of the length of our models was limited to three to six feet in one-foot increments. Figure 3 shows the three-foot model generated using non-proportional axis scaling. When comparing these two methods, the difference in the two shapes generated is obvious. The three-foot model made using non-proportional axis scaling can take on an entirely different shape, and may even have a different look and feel than the original. Since the look of the existing four-foot was considered a desirable one, it was decided that the family of products should appear as similar as possible.

|[pic] |[pic] |

| |[pic] |

Figure 3. Non-Proportional Axis Scaling

A derivative of non-proportional axis scaling is attribute scaling and was the method that was eventually used. In attribute scaling, point locations or attributes of the model are scaled to create the various shapes. In Figure 4, the location of four points s modified to generate 2 different cross sections. This type of scaling increases the design time for each product, but can also create more flexible design while maintaining shapes that have a similar look or feel. Figure 5 shows the various dimensions of the hull shapes that were produced. Both the overall length and radius were calculated by linear scaling, however the 'H' dimension or end radius is constant for the three and four-foot prototypes as well as the five and six.

|[pic] |[pic] |

Figure 4. Attribute Axis Scaling

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| | |

|[pic] | |

|Revolved cross section |Dimensions in inches |

Figure 5. Attribute Axis Scaling Summary

The reasoning behind using an attribute scaling method for this project was to increase the commonality of the various prototypes within the product family. By using the dimensions listed in Figure 5, the unique parts necessary for a finished prototype would be the following 3; the canopy, hull and center chassis. The remaining parts that are required to complete a working prototype could be shared by multiple products in the product family. For example, the supports for the three and four foot models could be the same, as could those for the five and six foot models. Due to the end radii having the same dimensions, the end chassis in each of these two pairs can also be identical. In addition, the clear plastic discs that make up the grill of each light could be designed such that the same disc could be used in multiple lights. Moreover, using postponement techniques in the manufacturing process the hull of one light could be used as the canopy of another. Such an example is seen in Figure 6 where the canopy of the five-foot prototype pictured is actually the same exact shape as the hull for the three foot light. Finally, additional customization could be gained by increasing the color of the plastic discs in the grill or the length of the supports.

|[pic] |[pic] |

Figure 6. Parts Diagram for Ivalo Lighting Fixture

Manufacturing Strategy

The light fixtures were manufactured in a 12 step process as outlined in figure 7. Models were created in IronCAD and from these models, cutter paths were generated in MasterCAM.

[pic]

Figure 7. Manufacturing Process Overview

[pic]

Figure 8. IronCAD Model

[pic]

Figure 9. MasterCAM toolpasses

The machined PVC was assembled from cut pieces of 48”x 24”x 2” stock glued together to provide the needed size and shape for the molds. A great deal of planning was put into laying out the cuts to optimize material usage and minimize scrap. The molds were then machined according to the cutter path in a CNC machine.

Figure 10. PVC Preparation

[pic]

Figure 11. PVC stock to be Machined

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Figure 12. CNC cutting of PVC

After the CNC process, some rough manual milling was required to remove large amounts of remaining stock. The molds were then sanded to provide a smooth surface for the fiberglass application. To further increase the smoothness of the mold and decrease porosity, a layer of car wax was applied to the mold. The molds were then coated with a thin layer of plastic release agent. The purpose of the release agent is to provide a sacrificial layer between the mold and the fiberglass so that the fiberglass does not bond to the mold itself.

Two layers of resin-saturated fiberglass were applied to each mold to provide sufficient strength. The fiberglass was then coated with Bondo body filler and sanded to produce a smooth, paintable surface.

[pic]

Figure 13. Fiberglass Application

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Figure 14. Bondo Application

The fixtures were then trimmed to size using a Dremel rotary cutter in a controlled level jig. Finally the fiberglass fixtures were painted with several layers of white paint to create a more pleasing aesthetic appeal.

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Figure 15. Dremel tool Jig

Figure 16 outlines the average time and cost allotted to each step of the manufacturing process. An average of 34 hours and $413 was spent on each of the four light fixtures produced.

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Figure 16. Time and Cost Summary

Course Question

One question that comes to mind when looking over the project; how does this project tie into the class? To answer this, recall the course question.

Course Question: How can product realization teams provide increased product variety at less cost for a highly competitive, global marketplace?

IVALO Lighting Answer: Designing (scaling) a product carefully can allow manufacturers to create multiple products using common parts and take advantage of economies of scale.

The light fixtures attributes were scaled from the original 4’ model in order to create the 3’, 5’ and 6’ models. This was done in a very similar fashion to the Boeing 737 aircraft and also the Rolls Royce RTM322 aircraft engine product families mentioned in class. Also, in the future the other components of the light will be produced and elements such as the plastic disks of the grill will be interchangeable between different sized light fixtures.

Conclusion

Using the 4-foot model from Ivalo Lighting Incorporated with which we were provided, we scaled to 3 ft., 5 ft. and 6 ft. models using an attribute scaling method. The CAD programs were altered and molds were machined using CNC machines and MasterCAM. The actual hull for the light fixture was made using fiberglass. The fiberglass was coated with bondo for a smoother and more durable finish, after which the edges were cut and the finished product was painted for final presentation. Overall, the project was a success, and the objectives were achieved. All four prototypes were manufactured. Since the molds were made of a durable material, a number of prototypes can be created quickly and cheaply.

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