The TLDR: Most important aspect of selecting material is going to be knowing what is important for your part. If its purely aesthetic choose the most affordable material that matches your look. If you need it to be hard, tough, and hold tight tolerances? Go with a high quality metal or alloy. Read the article below to see how to identify what your parts needs to rely on and which materials might pair best with that. Still not sure? Feel free to contact McGonigle's Advanced Manufacturing to talk with a professional who has helped others make this decision too.
Understanding the Purpose for your Design
Before delving into what materials to use, you need to know the intentions and specifications to your design are. One common way to recognize this is in terms of your designs Form, Fit, and Function. Your design's purpose and specifications significantly influence material selection. Knowing these three core concepts are crucial for informed decision-making as we explore various material options.
Form - The shape, size, feel, weight, finish and other visual parameters
Fit - Ability to be made a part of or become integral with another part or the design as a whole
Function - The ability to do the action it is designed to perform
These three categories will influence what material and budget your design demands. As you address what your Form, Fit, and Function (FFF) is, then you might recognize one category might be more influential over your final product then another. For example, a simple mug will mostly rely on its, Form to have one that visually appeal to the customer, but also its Function to be water proof, dishwasher safe, or other needs.
The Fit of a part is more common with things like puzzle pieces, building blocks, or adapters where the precise dimensions and ability to mate with another piece are integral to its overall goal.
Choosing the Right Material
Now that you know what your parts Form, Fit, and Function you can match the material that meets the needs that your design demands. Read below to show some material and what they are best known for. Here are some questions you can ask yourself that will guide you to the right material for your job.
Does my part need to be strong and resistant to wear?
Does my part need to withstand high/low temperatures?
Do I or my customer care if it is a certain color or texture?
What properties does my part need to have to complete its function?
Is my part meant to interact with people or with other components?
Are their any regulations or compliances that my parts need to meet?
Will my part be exposed to any elements or outside conditions?
Use those questions above and your understanding of Form, Fit, and Function to now pick what will be the right material for project!
Plastics:
Known for versatility and affordability, Plastics can cater to diverse applications and uses. Here's a closer look at some popular options
Machined Plastics
Material | Strengths | Drawbacks | Typical Applications |
Delrin | Tensile Strength, impact resistant, Low Friction, chemical resistant | Degrades in sunlight, flammable, experiences creep under constant load | Conveyor systems, rollers, housings, gears and bearings |
Acrylic | Clear/transparent, lightweight, weather resistant, UV resistance | low hardness, brittle, easy to scratch, low melting point | Signage & Displays, lighting fixtures, Art and Crafts, Screen and enclosures |
ABS | moderate strength and regidity, good temperature resistance, multiple available colors | degrades in sunlight, hazordous when manufacturing, non-biodegradble, not safe for food contact | toys, pipe fittings, model making, prototyping, luggage, electronic housings |
Molded or 3D Printed Plastics
Material | Strengths | Drawbacks | Typical Applications |
PLA | Easy to manufacture, low cost, wide color variety, many infill options to change properties | Degrades in sunlight, low temperature resistance, low strength | Prototyping, Visual representations, art, decoration |
Polycarbonate | Good tensile strength, rigid, impact resistant, UV resistant | chemical sensitivity, | Tools and equipment, automotive, lighting, sports |
PEEK/PEKK | Extreme Temperature resistance, High Strength, High precision, outstanding chemical resistance | expensive, hard to produce, low UV resistance, limited color options | toys, pipe fittings, model making, prototyping, luggage, electronic housings |
Nylon | High Tensile strength, excellent impact absorbtion, wide color options, prone to deform instead of break, wide array of polymers | Absorbs moisture quickly, prone to warping, more costly to mold | Rope, clips, gears, housing, mechanical parts, compliant mechanisims |
Metals
Metals can offer a wide range of applications both affordable and very expensive. Generally you might choose using metals over plastics due to constraints for strength, conductivity, durability, hardness or many other factors that come with metals you commonly know. Before picking a specific alloy, you should know that metals break down into two main categories, Ferrous and non-ferrous.
Ferrous Metals
Ferrous Metals are characterized by containing primarily iron. The term Ferrous is actually derived from the Latin word "Ferrum" which translates to Iron.
Ferrous Metals are known to be strong, durable, and able to withstand extreme environments and stresses.
Common examples of Ferrous metals are Iron, Stainless Steel, Nickel, and Carbon Steels.
Non-ferrous metals
Non-Ferrous metals, while not containing a majority of iron can still have a wide range of applications which their Iron rich counterparts also have, but mainly offer application specific strengths which would pull a customer towards their use. Very commonly a Ferrous Metal can be alloyed with another metal to bolster the strengths and weaknesses that each material can bring.
Common examples of Non-Ferrous metals are Aluminum, Copper, Zinc, and Titanium.
Choosing the right metal
Now that you now the two commons categories of metal you need to know what each metal is how it might impact your project. Unlike plastics, the price and quality of metals can very wildly from vendor to vendor. Use the chart below to see basic comparisons the type of metal and what sort-of price range you might find it in.
Name | Tensile Strength | Hardness | Price |
6061 Aluminum | 69 GPa | 93 | $ |
1018 steel - Cold Drawn | 190 GPa | 140 | $$ |
1018 steel - Hot rolled | 190 GPa | 130 | $$ |
718 Inconel | 190 GPa | 389 | $$$$$ |
304 Stainless Steel | 200 GPa | 170 | $$$ |
C-5 Titanium | 110 GPa | 310 | $$$$ |
CC140C Copper | 120 GPa | 110 | $$ |
G1800 Cast Iron | 180 GPa | 160 | $$ |
Now that you know
Understanding the differences between plastic, metals, and other material will unlock how you design your parts for affordability and effectiveness. Grasping the concepts of Form, Fit, and Function will help you narrow down the differences between materials and allow you to pick the best fit for your job. If you are still struggling then feel free to click the button below to get in contact for free by our team at McGonigle's Advanced Manufacturing! We are glad to help you with your project no matter the size or the challenges
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