Material is what your custom part will be made out of. You can select select a material from a list of common materials or specify a special material. For example you might select aluminum for an electronic chassis to minimize weight.
- Choose Job | Material. The material types shown depend on your design. For example, if your part is configured for injection molding, only plastics will be enabled.
- Check Show only recommended materials if you want to see the recommended materials. (Point your mouse to this option for more detail.)
- In the grid select the desired material by clicking on your selection. Use the columns of information* to help you decide on the best material for your job. Ignore columns not of concern to your requirements. If you don’t have any specific requirements, consider selecting the lowest cost (VRCost column) steel, aluminum or plastic. See Material Grid and Properties of materials.
- Choose the lower checkbox settings as needed.
- Click OK.
* The data presented in the material dialog was collected from several sources. Although the sources are believed to be reliable, the accuracy of the data is not guaranteed. The data is intended as a general guide. If one or more parameters are critical to your design you should verify the data independently. Please contact eMachineShop with any corrections.
You can select a material other than what is offered in the material list. For example, you might want to order a part made of a specific alloy or a precious metal.
To request a special material:
- Choose Job | Material.
- Select the material closest to the desired material – this allows for the pricing mechanism to give an approximate price for your job.
- Check Request special material.
- Enter a description of the desired material. It might save time to enter a suggested vendor if you have one.
- Click OK.
Note: eMachineShop does not research cost, availability or sourcing of specific materials until an order is placed. If the specific material requested cannot be acquired a suitable substitute might be recommended, which you can approve or decline. Special materials are acquired as needed.
See the text in Job | Material | Request Special Material for applicable terms.
A certificate of material compliance is a paper document that confirms that the material you ordered conforms to the specifications of the material. You can request a certificate of material compliance. For example, you might want to request a certificate when significant problems might occur for you if the material does not conform to specs. The certificate adds an additional cost.
You can allow or disallow substitution of a different (but similar) material. For example, you might choose to allow substitution for a non-critical bracket but you will likely want to choose to disallow substitution where safety is a concern.
To request a certificate of material compliance:
- Choose Job | Material.
- Check Certificate of compliance.
- Click OK.
To control material substitution permission:
- Check Allow Substitution if you are flexible on the material selection. This can result in earlier delivery and minimize the chance of any delay.
- Uncheck Allow Substitution if you are not flexible on material.
At eMachineShop, pre-shaped stock is material that comes in special forms other than sheets, plates, blocks or rods. For example, a round or square tube is considered a pre-shaped material. You might be able to reduce cost by specifying a pre-shaped material. For example, a shape that can be made by drilling holes in a hollow tube requires less machining time than starting with a block of material or rod. A part having a one inch square cross section may be more efficient to cut from one inch square bar stock. Note that specifying to use pre-shaped stock does not always reduce price.
To specify pre-shaped stock:
- In the Top view draw the cross section shape.
- Choose Line | Machine | Auto | Stock Material Wall.
- Set the Z value of the outer line to the length of the extrusion.
- Set the Z value of any inner lines to Air Inside.
- Typically in one or more side views, draw any desired features such as holes, notches, slots, etc.
- Add Comments To Machinist text (e.g. “Use stock shape equivalent to mcmaster.com #123456).
- If you want to approve the price or delivery time before your job is processed, add Comments To Machinist “For quotation only”. Your order will not be processed unless you direct eMachineShop to proceed.
You can specify the color of your parts in multiple ways. For example, you can select a powder coat finish for a metallic blue carburetor body.
To specify the color your your part:
- Select a material color in the Job | Material dialog. For example, it lists Acetal Black and Acetal White. If the color you want is listed, simply select the appropriate row of the material table.
- For more materials uncheck the “Show Only Recommended Materials” checkbox in the Materials dialog.
- If you need another material you can check “Request Special Materials” and enter the particular color and type of material you need.
- Choose Job | Finishing to select a colored finish. Powder Coat is one of the most economical finishes offering a wide variety of colors.
- Of course, you can choose to have eMachineShop create your part and paint it upon receipt.
The materials grid shows you various information about the different materials. You can access the grid at menu Job | Materials.
Below is a brief explanation of each field with links to more detailed information.
VRCost – approximate relative material cost by weight, but selecting a lower cost material may not always give the lowest cost job**. The lowest VRCost may not yield the lowest part cost because many factors effect the total job cost. For example, a lower cost material might be harder to machine or be more expensive to ship due to increased weight. And a material of the same cost as another might be less expensive because it’s weight is lower. The VRCost value is most relevant to job cost within a similar class of materials such as steels.
Machinability – How well the material machines. Selecting a material with good machinability may reduce cost and improve surface finish.
Usage – Some common uses for the material. There is generally no need to be concerned if your usage is not listed as most materials have too many uses to list.
Density – How heavy a material is per volume. For example if one material is twice as dense as another, your part will weigh twice as much if made out of the more dense material.
Melting point – The temperature at which the material changes from solid to liquid.
Hardness – How resistant material is to permanent shape change when a force is applied.
Hardness scale – The scale used for the Hardness value.
Yield strength – The stress at which a material begins to deform plastically.
Shear strength – Strength of a material against the type of yield or structural failure where the material or component fails in shear.
Tensile strength – Maximum stress a material can withstand while being stretched or pulled before necking which is when the material’s cross section starts to significantly contract.
Thermal conductivity – Ability to conduct heat.
Modulus of elasticity – Tendency to be deformed elastically (non-permanently) when a force is applied.
Weldability – How well material can be welded.
Availability – Approximate time in days it takes eMachineShop to acquire the material, which may influence the time to ship your parts.