How can I automate CNC machining time estimations from 2D PDF CAD drawings?

Below is an outline of how you could approach this using n8n:

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1. Ingest the PDF Drawing

• Webhook/File Trigger:
Use an n8n Webhook node or a file upload node to receive or monitor the incoming 2D PDF CAD drawing.
This node will kick off your workflow whenever a drawing is uploaded.

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2. Process the PDF Using Self-Hosted Tools

Because n8n does not offer a built-in “CAD-to-data” node, you’ll need to integrate a self-hosted process to extract measurements and material data from the PDF. Here are a couple of options:

• OCR/IDP Solutions:

• Tesseract OCR: You can install and run Tesseract (or a similarly self-hosted solution) to extract text data from the PDF.
• Custom Script with OpenCV and PDF Parsing Libraries: If you require more than OCR (e.g., detecting dimensions or technical details), you might combine OCR with image processing libraries.

• Integration with n8n:
Use the Execute Command node or an HTTP Request node (if you expose your processing service as an API) to trigger your self-hosted parsing/analysis tool.
For example, your custom service could take the PDF file as input, process and return a JSON object containing the extracted measurements and specs.

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3. Calculate Machining Time Estimates

Once you have the relevant data from the drawing, use a Function node to crunch the numbers.
Here’s a simple example of what that Function node might look like:

JAVASCRIPTCopied
// Example: process extracted data and calculate machining time estimates

// Assume previous node output is an array of JSON items.
// For instance:
// {
//   "data": {
//      "thickness": 12,       // in mm
//      "width": 100,          // in mm
//      "material": "Aluminum"
//   }
// }

const item = items[0].json;

// Use your own machining formulas based on dimensions and material
let machiningTime;
if (item.material === 'Aluminum') {
  machiningTime = (item.thickness * item.width) / 50; // Example calculation for Aluminum
} else {
  machiningTime = (item.thickness * item.width) / 40; // Example calculation for other materials
}

return [{
  json: {
    ...item,
    machiningTime,
  }
}];

Update the calculation logic based on your actual formulas and machine performance data.

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4. Decide the Optimal CNC Machine

With the calculated machining time estimates, you can then determine which CNC machine fits best. For example, if you have different machines with varying speeds and capabilities:

• Conditional Routing:
Use an IF node to compare the estimated times against thresholds.
Based on the result, direct the workflow to:

• Notify you with the recommendation.
• Automatically schedule the job on the recommended CNC machine (if your machines have an API you can call).

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5. Complete Your Workflow

• Notifications/Integration:
Finally, you can add nodes to send notifications (via email, Slack, etc.) or trigger further processing in your CNC machine management system.

• Execution and Logging:
Optionally, store the results in a database (using the respective n8n node) or log the details for future reference.

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Final Notes

• While n8n’s core nodes provide a powerful way to route and manage data, the key for this use-case is integrating a self-hosted PDF-to-data solution.
• Consider building a small local API around an OCR and PDF parsing library if you need to keep client data private.
• n8n’s flexibility will allow you to call your custom solution and then apply custom processing (as shown in the Function node example).

By combining these components, you can create a private and automated workflow on n8n that meets your requirements for calculating machining time estimates.

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This approach leverages the strengths of n8n to orchestrate your custom PDF processing and decision logic—all while keeping your client data on your premises.