Calculating 3D Print Costs with Spoolman API and Python

calendar Jan 10, 2025 · 6 min read · 3d printing python  ·
Share on: linkedin copy

As a 3D printing enthusiast, I've often grappled with accurately calculating the cost of my prints. While slicers provide estimates of filament usage, they don't account for the actual cost of the filament used, especially when dealing with multiple spools or varying filament prices. To solve this, I developed a Python script that calculates the real cost of a 3D print by leveraging the Spoolman API. In this blog post, I'll walk you through the motivation behind the project, the features of the script, and how you can use it to accurately estimate your 3D printing costs.

The Challenge

Estimating the cost of a 3D print isn't straightforward when:

  • Multiple Spools Are Used: Prints may require filament from different spools, each with different prices, materials, or remaining quantities.
  • Varying Filament Prices: The cost per gram can vary significantly between filament types and vendors.
  • Slicer Limitations: While slicers provide filament usage estimates, they don't integrate actual spool data or costs.

This led me to create a solution that considers the actual filament used from specific spools, providing a more accurate cost calculation.

Introducing the Filament Cost Calculator

The Filament Cost Calculator is a Python script that:

  • Fetches Spool Data: Retrieves information about your spools from the Spoolman API, excluding any archived spools.
  • Calculates Costs for Multiple Spools: Allows you to input filament usage for multiple spools, summing up the total cost.
  • Flexible Unit Input: Accepts filament usage in grams or meters, with units specified directly in the input (e.g., 100g, 50m).
  • Provides a Summary Report: Displays a formatted summary of all filaments used and their individual costs at the end.

You can find the script on GitHub: Spoolman Multi-Spool Cost Calculator

How It Works

1. Fetching Spool Data

The script connects to the Spoolman API to retrieve information about your spools:

  • Excludes Archived Spools: Only active spools are displayed for selection.
  • Displays Spool Details: Shows the spool name, price, material, color, and other relevant information.

2. User Input

  • Spool Selection: You select the spools used in your print by entering the corresponding numbers.
  • Filament Usage: Enter the amount of filament used for each spool, directly specifying the unit (g for grams or m for meters). If you omit the unit, the script assumes grams.

3. Cost Calculation

  • Mass per Meter Calculation: For inputs in meters, the script calculates the mass per meter using the filament's diameter and density.
  • Cost per Gram: Calculates the cost per gram based on the spool's price and initial filament weight.
  • Total Cost: Multiplies the filament used by the cost per gram to determine the cost for each spool, summing up the total.

4. Summary Report

At the end, the script provides a summary table:

  • Spool Name
  • Filament Used
  • Unit (g or m)
  • Cost

Setting Up the Script

Prerequisites

  • Python 3.6 or higher

  • Required Libraries: Install the necessary Python packages using:

    1pip install requests python-dotenv

Configuration

  1. Clone the Repository

    1git clone https://github.com/vechiato/spoolman-multi-spool-cost-calculator.git
2cd spoolman-multi-spool-cost-calculator

  2. Set Up Environment Variables

    Create a .env file in the project directory:

    1# Spoolman API URL (default is http://localhost:9712/api/v1 if not set)
2SPOOLMAN_API_URL=http://your-spoolman-host:port/api/v1
3
4# Spoolman API Key (if required)
5SPOOLMAN_API_KEY=your_api_key_here
    • Replace http://your-spoolman-host:port/api/v1 with your Spoolman API URL.
    • If you don't set SPOOLMAN_API_URL, the script defaults to http://localhost:9712/api/v1.

Using the Script

Run the script using Python:

1python calculate_filament_cost.py

Step-by-Step Guide:

  1. Select Spools

    The script lists available spools:

    1Available Spools:
2 1. PLA Red (ID: 1) Price: $16.49 Material: PLA Color: ff0000
3 2. PLA White (ID: 2) Price: $10.99 Material: PLA Color: ffffff
4 3. NYLON GREY (ID: 3) Price: $28.99 Material: NYLON Color: 808080
5 4. PETG BLACK (ID: 4) Price: $15.99 Material: PETG Color: 000000

    Enter the number corresponding to the spool you wish to use.

  2. Enter Filament Usage

    When prompted, enter the amount of filament used with the unit:

    1Enter filament used for the print (e.g., '100g' or '1.5m'): 100.34g

  3. Add Additional Spools

    After each spool, you can choose to add another:

    1Do you want to add another spool? (y/n): y

  4. View the Summary Report

    Once done, the script displays a summary:

    1 Summary of Filament Usage:
2 Spool Name                             Filament Used        Unit    Cost
3 ---------------------------------------------------------------------------
4 PLA Red                                    100.34             g      1.65
5 PLA White                                   53.21             m      1.74
6 ---------------------------------------------------------------------------
7 Total Cost:                                                          3.40

Example Output

 1Available Spools:
 21. PLA Red (ID: 1) Price: $16.49 Material: PLA Color: ff0000
 32. PLA White (ID: 2) Price: $10.99 Material: PLA Color: ffffff
 43. NYLON GREY (ID: 3) Price: $28.99 Material: NYLON Color: 808080
 54. PETG BLACK (ID: 4) Price: $15.99 Material: PETG Color: 000000
 6...
 7
 8Select a spool by number: 1
 9
10Selected Spool: PLA Red
11Spool Cost: $16.49
12Remaining Filament Weight: 912.13 grams
13Material: PLA, Diameter: 1.75 mm, Density: 1.24 g/cm³
14
15Enter filament used for the print (e.g., '100g' or '1.5m'): 100.34g
16
17Cost for this print: $1.65
18
19Do you want to add another spool? (y/n): y
20
21Select a spool by number: 2
22
23Selected Spool: PLA White
24Spool Cost: $10.99
25Remaining Filament Weight: 440.00 grams
26Material: PLA, Diameter: 1.75 mm, Density: 1.24 g/cm³
27
28Enter filament used for the print (e.g., '100g' or '1.5m'): 53.21m
29
30Cost for this print: $1.74
31
32Do you want to add another spool? (y/n): n
33
34Summary of Filament Usage:
35Spool Name                             Filament Used        Unit    Cost
36---------------------------------------------------------------------------
37PLA Red                                    100.34             g      1.65
38PLA White                                   53.21             m      1.74
39---------------------------------------------------------------------------
40Total Cost:                                                          3.40

Benefits of This Approach

  • Accurate Cost Estimation: By considering actual spool prices and filament used, you get precise cost calculations.
  • Handles Multiple Spools: Ideal for prints that require different filaments or when spools have varying remaining quantities.
  • User-Friendly: The script provides clear prompts and handles inputs flexibly.
  • Customizable: You can modify the script to suit your needs, such as integrating with your slicer's output or adjusting for different currencies.

Future Enhancements

  • Integration with Slicers: Automating the extraction of filament usage directly from slicer output files.
  • Graphical User Interface: Developing a GUI for easier interaction.
  • Exporting Reports: Adding functionality to export the summary as a CSV or PDF for record-keeping.

Conclusion

Accurately calculating the cost of your 3D prints is essential, whether for personal budgeting, quoting clients, or managing resources. By leveraging the Spoolman API and this Python script, you can gain better insights into your printing costs and make informed decisions.

Check out the project on GitHub: Spoolman Multi-Spool Cost Calculator

I hope you find this tool as useful as I have. Feel free to contribute to the project or suggest enhancements!

Acknowledgements

Happy printing!

comments powered by Disqus