Material cost is not just the amount of material that makes up the final sintered parts, nor is it the amount of material labeled ‘Total Powder’ in PreForm. Material cost can be calculated by adding the sintered powder to the powder that is not sintered but also cannot be recycled into your next print. 

This means that this formula changes based on the type of material used, refresh rate, packing density, and cost of powder (whether or not it is discounted in bulk). The latest version of PreForm calculates material cost based on the following formula, and will prompt you to enter the cost per kilogram of material (which can vary from $45/kg to $100/kg depending on the material and the amount ordered).

• CM = Material Cost per Part

• M = Mass per Part

• PM = Material Price per kg*

• RR = Refresh Rate

• PD = Packing Density

* The best way of reducing cost per part is through bulk powder discounts. Formlabs SLS Powders can cost as low as $45/kg for bulk orders.

Notes: 

• This model assumes that RR > PD

  • Though this happens rarely, if packing density is equal to or higher than the refresh rate, then you’ll have less unused powder for your next build than the refresh rate states, and you’ll need to supplement with a higher proportion of fresh powder. 

  • Spending more time post-processing in the Fuse Sift can create marginally more powder for recycling, but at the cost of the added labor. 

  • Once packing density matches or even exceeds your refresh rate (very difficult to do unless you’re printing solid blocks), your cost per part is simply the cost per gram of powder the parts use. 

• Unlike MJF 3D printing, the Fuse Series does not have to factor in the cost of a binding agent into material costs.

• Regardless of build height, Fuse Series SLS powders’ refresh rates do not change — unlike MJF printers, where a shorter build may have a different refresh rate than a taller one.

• The Fuse Series has no limit on packing density as long as minimum space between parts is maintained — PreForm will auto apply 5 mm space between parts, but this is conservative, and most parts can be spaced as closely as 2 or 3 mm apart before there is danger of fusing parts together or degradation in surface finish. 

  • MJF printers often limit packing density, and even for MJF builds that reach a 15% packing density, the required refresh rate is 40%, meaning you’re always going to be using more ‘fresh’ powder for new builds and will be less able to efficiently recycle your unsintered powder.

Packing density refers to how much of the build chamber is being sintered into parts, though you can also understand it as how densely your parts are packed together. PreForm’s Packing Density calculations are by mass, while other tools (or assumptions) may use volume. Sintered parts are nearly twice as dense as unsintered powder, so mass packing density will be larger than the volumetric packing density found using the build chambers’ internal dimensions. 
The best way to drive down cost per part is to fill any large gaps between parts with other parts, or to orient them in such a way as to take advantage of features that can be printed within others’ cavities or negative spaces.*

PreForm’s auto-packing feature is the fastest way to get the best packing density while maintaining proper tolerances between parts. PreForm starts auto-arraying models with 5 mm in between them, although this is conservative and can be adjusted manually, with a recommended minimum space in between parts of 2 mm. 

*Some Fuse Series users have part files like clips, connectors, or discs that they keep on hand to add into builds that need better packing density in order to better match the materials’ refresh rates.

PreForm displays packing density along with the total powder usage. To most efficiently use your powder, you should try to match packing density to refresh rate. For Nylon 12 Powder parts, aim for a packing density of 30%. This way, 30% of that build will be sintered powder, and 70% will be unsintered powder. For your next print, all that unsintered powder can be recycled into the new build chamber according to the recommended refresh rate. 

*Though each of these builds is taking up the same amount of volume when combining sintered and unsintered powder, the Total Powder weighs differently for each, because sintered powder has twice the density of unsintered powder, so the same volume will weigh more with a higher packing density. 

Though trying to match packing density to refresh rate (getting packing density as high as possible) reduces part cost by making your powder recycling more efficient, in the examples above, you can see that latticing or hollowing parts reduces cost per part more significantly. However, this is just because of the significantly lower amount of powder used overall. If you can hollow or lattice your parts, or use generative design to create organic, efficient structures, this can reduce your cost per part (even when it also reduces pack density). 

PreForm offers a Hollow option as well as a Hole option, so that when you hollow your models, you can add a drainage hole to get the unsintered powder out from the hollowed part (this would be difficult with a cube part like this, simply used as an example). 

The average business in the US pays just over $0.16 per kWh for electricity. The Fuse 1 and Fuse 1+ 30W printers use about 5 kWh of electricity for a full 24-hour build of densely packed parts. The Fuse Sift and Fuse Blast use about 1 kWh of electricity for a 10-minute Sift and 1 kWh for two, 15-minute automated Blast cycles, combining for a total of about 7 kWh of electricity for one 24-hour production volume print with a packing density of about 30%. This equates to about $1.12 per day of electrical consumption. When dividing this cost by the number of parts produced, it often becomes a negligible addition to the formula.

Most businesses do not factor in equipment cost when calculating cost per part, often purchasing equipment cost with capital expenditure funds and materials, electricity, and labor with operating expenditure funds. However, many businesses do use their cost per part (and savings when compared to other production methods) for calculating their ROI. In this scenario, the complete Fuse Series SLS ecosystem, at less than $60,000, is a scale factor more affordable than other 3D printing options like traditional MJF or SLS printers, and small businesses can get started producing parts with just a printer and Fuse Depowdering Kit for $25,000. Extra production capacity can be easily achieved by adding extra build chambers at $3,999, to enable 24/7 production.

Labor costs depend entirely on your business model, but to create your own labor cost estimate, you can use use the following estimates for the labor required for each build. 

• File Prep and Upload: 10-20 minutes (less when printing repeated production builds)
• Printer preparation: 5 minutes
• Printing: 0 minutes hands-on labor
• Cooling in printer: 0 minutes hands-on labor
• Transferring to Fuse Sift: 1 minute
• Cooling in Fuse Sift before unpacking: 0 minutes hands-on labor
• Extraction (sifting): 10-20 minutes, dependent on part quantity (Using Fuse Blast reduces Sifting time by up to 80%)
• Transfer to Fuse Blast: 1 minute
• Blasting: 0 minutes hands-on labor
• Printer Maintenance: 12 minutes
• Fuse Sift Maintenance: 2 minutes
• Fuse Blast Maintenance: 2 minutes

In the following production scenario, we’ll calculate the cost per part based on a medium-volume manufacturing workflow with the following inputs:

• One employee with a $40/hour wage

• Complete Fuse Series SLS ecosystem with two extra build chambers ($65,440)

• Five days a week, 50 weeks a year

• Drone manufacturing, with an average order of several hundred drone components each week 

• Part: Drone frame base, designed by Building Momentum

• Bulk discount at 30%, ordering 200 kg of Nylon 12 Powder at a time, $65/kg

Equipment Amortization Schedule: 

Equipment Cost (Fuse 1+ 30W Complete Package w/ 2 extra build chamber): $65,440

Working Days: 250/year

Amortization Timeline: 5 years 

65,440/1500 working days = 43.63

43.63/120 parts per day = $0.36

$0.36 per day is the amortized cost of the printer over 5 years. Though this example shows what nearly 100% utilization (with an efficiently packed build, two printing shifts per day, and thousands of the exact same part) looks like, even if the utilization rate were half this, the amortization of the printer would still be extremely efficient. 
 

Material: $0.71

Amortized Cost of Equipment: $0.36

Labor: $0.34

TOTAL COST PER PART: $1.41

Though material functionality, surface finish, dimensional accuracy, and machine consistency are all important qualities to consider when choosing a production method, the biggest concern many manufacturers have is cost. Traditional methods of production like injection molding are typically more cost-efficient when producing tens or hundreds of thousands of parts, and outsourcing to a 3D printing service bureau may make sense if you need only one or two parts. However, with the introduction of accessibly priced, powerful 3D printers like the Fuse Series, in-house manufacturing can be done efficiently and cost-effectively. 

Setting up a manufacturing workflow that can deliver on a per part cost of less than a dollar is possible with the Fuse Series. As with the above example, you can produce close to a thousand parts a week with only an hour of hands-on labor each day, less than 100 square feet of space, and an equipment cost of just $65,440. The drone frame base parts used in this scenario would cost only $1.41, and with even greater bulk powder pricing tiers available, could cost even less.

Bringing SLS in-house for manufacturing doesn't have to be complicated or expensive. To learn more about getting started with a customized cost per part calculation, contact our team.