Week 17

Wild Card Week

This weeks assignment was to Design and produce something with a digital fabrication process not covered in another assignment. Possibilities include (but are not limited to) composites, textiles,biotechnology, robotics, and cooking.

I tried to make a lot of things for this week but due to some reason or the other I was not able to finally make them.......

I decided to make something out of composites....... and the software for designing would be Fusion 360

Introduction to Composites

A composite material (also called a composition material or shortened to composite, which is the common name) is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure, differentiating composites from mixtures and solid solutions.

Composites are made up of individual materials referred to as constituent materials. There are two main categories of constituent materials: matrix (binder) and reinforcement. At least one portion of each type is required. The matrix material surrounds and supports the reinforcement materials by maintaining their relative positions. The reinforcements impart their special mechanical and physical properties to enhance the matrix properties. A synergism produces material properties unavailable from the individual constituent materials, while the wide variety of matrix and strengthening materials allows the designer of the product or structure to choose an optimum combination.

Engineered composite materials must be formed to shape. The matrix material can be introduced to the reinforcement before or after the reinforcement material is placed into the mould cavity or onto the mould surface. The matrix material experiences a melding event, after which the part shape is essentially set. Depending upon the nature of the matrix material, this melding event can occur in various ways such as chemical polymerization for a thermoset polymer matrix, or solidification from the melted state for a thermoplastic polymer matrix composite.

~Source: Wiki

When Should you use Composites ?

As with all engineering materials, composites have particular strengths and weaknesses, which should be considered at the specifying stage. Composites are by no means the right material for every job.

However, a major driving force behind the development of composites has been that the combination of the reinforcement and the matrix can be changed to meet the required final properties of a component. For example, if the final component needs to be fire-resistant, a fire-retardant matrix can be used in the development stage so that it has this property.

Weight reduction

>The primary reason composites are chosen is improved specific strength / stiffness (strength / stiffness specific per unit weight).

>This helps to reduce fuel use, or increase acceleration or range in transport.

>It allows for easier, faster installation or faster movement of robot arms and reduces supporting structures or foundations.

>It improves topside stability in vessels and offshore structures and buoyancy for deep sea applications.

Durability and maintenance

>Composites don’t rust, which is crucial, especially in marine and chemical environments. The need for maintenance and painting is reduced or eliminated.

>Composite bearings for marine engines and bridges need no lubrication and don’t corrode.

>Combine the excellent fatigue resistance, and composites can increase product lifespan by several times in many applications.

Added functionality

>Composites are thermal insulators which is good for fire and blast protection or cryogenic applications.

>Electrical insulation is useful for railway lineside structures and radar transparency. A conductive mesh or coating can be integrated if needed, e.g. to reflect radar or divert lightning.

>Sensors, electronics and cabling can be embedded.

Design freedom

>Composites design allows for freedom of architectural form.

>Many parts can be consolidated into one, and stiffeners, inserts, etc. can be integrated in-mould.

>Composites can be tailored to suit the application by choosing the constituent materials and embedding extra functionality.

~Source: CompositeUK

The Lamp

The first thing I started was a lamp.... and make a postive of the Lamp.....For making a lamp I used very simple approach .... I made a sketch and rotated it ... then I made fillet to smooth the edges...

Now I used fillet to make the edges smooth

Now that the positive of the mould was ready..... I decided to make Negetive of the mould..... and for doing the same, I used the offset function of the sketch in FUSION 360 and trimmed some lines.

Now Revolve operation was done

Download Fusion Files (Lamp Shade)

Problem with this design

Now it was time to make the tool path to mill the designs

Soon I realized the size of the lamp is way more than the material which was available so I decided to scale it down, but the material which was available was (152X100X38)mm^3 (Length X Width X Height), it was quiet small, the lamp shade would have been looked like a bowl..... So I decided to switch the design and lets make a bowl instead, It can be used too....... handy thing on the table to put on your small small components ........ Convincing ? Well, I was convinced to go ahead with this ........

Available Material

The avialable material was only 90X100X40 mm, which is way smaller for the lamp...... So I decided to make a Bowl which would lie in these dimensions.

The Bowl

For making the Bowl ..... I followed the same process....

1. I made a rectangle

2. I made the fillets, the postive of the bowl is ready

3. I Exported the STL file

4. I took Offset and made a negetive of the bowl

5. I Exported the STL file

Sketch : This step would be involving the 2D drawing of the Bowl

Extrude : In this step 2D Model is transformed to 3D, using the Extrude operation, the material was extruded 35mm only as the maximum material height was 40mm.

Fillets : Now Fillets were made to make the edges smooth.

Now this would be the final positive model of the bowl..... I have exported this to STL

Tadaaaa...... The positive of the design is ready .....

Now that the postive of the design is ready ..... I started with making the NEGETIVE of the design.....

To do this I UNDO all the steps and went back to the sketch state and then followoed these steps.

Taken Offset

Offset is important as it'll create the space for the material to fit in when it'll be compressed.

Extrude: This time the Extrution was about 38mm, this is to make sure that the stacked layer fit in the cavity between the positive and the negetive.

Extrude middle plane

Make fillets : This is same as we did in the postive of the bowl.

Now the negetive of the design is also ready ......

Its time to make the tool path

Download Fusion Files (Bowl)

Tool Path

This procedure has been documented in week 10 i.e Moulding and Casting week (LINK)

Here are few screen shots of the tool path creation of the Bowl

Download CNC Files (Bowl)

Milling

Now its time to mill the design

This procedure to calibrate the machine has been documented in week 8 i.e Computer controlled cutting (LINK)

Milling Postive

Milling Negetive

After Milling

Composite

Now it was time to make the Bowl using composites...... till now my friends have started reffering as Ash tray ...... well, coming to the point..... I am going to use Fiber glass, Paper and Semi synthetic Sheet along with Epoxy.....

I started with taping on the postive and the negtive of the bowl

This step is very cruicial as tape would be preventing the epoxy to stick on the wood, an making it immpossible to open after drying up.

Here is the process I followed ..... Epoxy >> Material 1 Layer >> Epoxy >> Material 2 Layer >> Epoxy >> Material 3 Layer >> Epoxy >> Material 1 Layer >> Epoxy >> Clamp .....