Convert and Export: PLT Export for SolidWorks (formerly HPGL Export for SolidWorks) Best Practices

How to Use PLT Export for SolidWorks (formerly HPGL Export for SolidWorks) for Precision OutputsProducing precise, reliable outputs from SolidWorks often requires exporting vector data in formats compatible with plotters, cutting tables, and other CNC devices. PLT (HPGL) is a widely supported vector format that preserves linework, layers, and pen information. This guide explains how to use PLT Export for SolidWorks (formerly HPGL Export for SolidWorks) to produce accurate, manufacturing-ready files, with practical tips for setup, troubleshooting, and quality control.

What is PLT/HPGL and why it matters

PLT (Plotter File) typically uses the HPGL (Hewlett-Packard Graphics Language) command set. It describes vectors using pen up/pen down commands, coordinates, and basic drawing primitives. Many plotters, vinyl cutters, laser cutters, and CNC machines accept PLT/HPGL because the format is compact, precise, and retains separate drawing layers or pens.

When to use PLT/HPGL

• When sending 2D vector artwork to plotters, cutters, or engravers.
• When you need exact line coordinates rather than rasterized images.
• When your downstream workflow expects pen/layer information (e.g., separate cutting vs. etching passes).

Preparing your SolidWorks model for PLT export

1. Clean up the drawing or sketch
   • Remove unnecessary annotations, dimensions, and construction geometry.
   • Convert filled areas or hatches to outlines if the target device doesn’t support fills.
2. Use 2D drawing views
   • Export from a SolidWorks Drawing (.slddrw) or use flattened 2D views of parts/assemblies to ensure only planar geometry is exported.
3. Set line types and thicknesses deliberately
   • Many devices ignore stroke weight; use distinct layers or colors to differentiate operations (cut vs. engrave).
4. Snap and tolerance checks
   • Ensure endpoints and intersections are coincident to avoid tiny gaps that cause extra tool moves.
5. Scale and units
   • Decide whether to export in millimeters or inches. Confirm the target device’s unit expectations.

Exporting with PLT Export for SolidWorks

1. Install and enable the PLT Export add-in (if required)
   • Ensure the correct plugin (formerly HPGL Export) is installed and active in SolidWorks Add-Ins.
2. Select the drawing or view to export
   • Open the drawing file and activate the view(s) you want to export.
3. Configure export options
   • File units: choose mm or inches.
   • Precision/coordinate resolution: higher resolution reduces rounding errors but increases file size.
   • Layer/pen mapping: map SolidWorks colors or layers to pen numbers used by your plotter/cutter.
   • Output type: choose between single-file PLT or multiple PLT files for different layers/pens.
4. Export and name the file
   • Use a clear filename indicating scale, units, and version (e.g., partX_1to1_mm_2025.plt).

Pen and layer management (best practices)

• Use a consistent color-to-pen convention (e.g., red = pen 1 for cuts, blue = pen 2 for etches).
• Map annotation and dimension layers to be excluded from the PLT export.
• Where the exporter allows pen speeds or delays, set values that match your machine’s requirements.

Handling filled areas, hatches, and text

• Filled areas: convert to outlines or polylines; solid fills often export as dense hatch patterns that some devices can’t process.
• Hatches: simplify or convert hatch patterns to single boundary polylines to avoid excessive plotting commands.
• Text: convert text to curves/geometry to ensure consistent fonts on the target device. Confirm acceptable minimum font sizes.

Advanced options for precision

• Coordinate scaling and integer precision: some devices expect integer coordinates; configure scaling so coordinates remain whole numbers without losing resolution.
• Arc handling: choose whether to export arcs as true HPGL arc commands or approximate with many small line segments—true arcs reduce file size and preserve smoothness.
• Optimize path order: use exporter settings (if available) to minimize pen-up moves or sort by toolpath to reduce machine runtime.

Verifying the exported PLT file

1. Preview in a PLT/HPGL viewer
   • Use a viewer to check for missing entities, unexpected layers, or scale issues.
2. Run a dry run on the target machine (no tool engaged)
   • Observe travel paths and detect collisions or unexpected moves.
3. Check coordinate extremes
   • Ensure nothing has been shifted or flipped (Y-axis inversion is a common issue).
4. Validate units
   • Measure a known dimension in the exported file to confirm matching units and scale.

Troubleshooting common issues

• Missing lines or entities: ensure those elements are on visible/printable layers; convert unusual features to standard geometry.
• Broken or open paths: tighten snapping/tolerance settings and use cleanup tools to join segments.
• Incorrect scale or flipped axes: verify export unit settings and any “flip Y” or origin options in the exporter.
• Excessive file size: simplify hatches/fills, reduce coordinate precision, or export arcs as arc commands instead of many segments.
• Font mismatches: convert text to curves before exporting.

Workflow example (step-by-step)

1. Prepare drawing: hide dimensions, convert filled areas to outlines, set colors for operations.
2. Activate PLT Export add-in in SolidWorks.
3. Open File > Save As > choose PLT/HPGL format.
4. Configure: units = mm, precision = high, map colors to pen numbers, arcs = true arcs.
5. Export to partX_mm_1to1.plt.
6. Open exported file in PLT viewer; verify dimensions and pen mapping.
7. Perform a dry run on cutter/plotter.
8. Execute production run.

Quality control checklist

• Dimensions verified in exported PLT match SolidWorks drawing within required tolerance.
• Layers/pens correctly mapped and annotations excluded.
• No tiny gaps or open profiles that could cause extra tool paths.
• File preview and dry run show expected behavior.

Conclusion

Using PLT Export for SolidWorks (formerly HPGL Export) effectively requires careful preparation of drawings, thoughtful layer/pen mapping, and verification steps to ensure precision. With correct setup—units, precision, arc handling, and path optimization—you can produce clean, manufacturable PLT files for plotters and CNC devices.