diff --git a/src/libslic3r/calib.cpp b/src/libslic3r/calib.cpp
index d694c2e455..0ba04478f9 100644
--- a/src/libslic3r/calib.cpp
+++ b/src/libslic3r/calib.cpp
@@ -32,7 +32,7 @@ namespace Slic3r {
         auto& writer = mp_gcodegen->writer();
         std::stringstream gcode;
         const double lw = 0.48;
-        Flow line_flow = Flow(lw, 0.2, mp_gcodegen->config().nozzle_diameter.get_at(0));
+        Flow line_flow = Flow(lw, 0.2, m_nozzle_diameter);
         const double len = m_digit_len;
         const double gap = lw / 2.0;
 
@@ -228,8 +228,8 @@ namespace Slic3r {
 
     std::string calib_pressure_advance_line::print_pa_lines(double start_x, double start_y, double start_pa, double step_pa, int num) {
         auto& writer = mp_gcodegen->writer();
-        Flow line_flow = Flow(m_line_width, 0.2, mp_gcodegen->config().nozzle_diameter.get_at(0));
-        Flow thin_line_flow = Flow(0.44, 0.2, mp_gcodegen->config().nozzle_diameter.get_at(0));
+        Flow line_flow = Flow(m_line_width, 0.2, m_nozzle_diameter);
+        Flow thin_line_flow = Flow(0.44, 0.2, m_nozzle_diameter);
         const double e_calib = line_flow.mm3_per_mm() / 2.40528; // filament_mm/extrusion_mm
         const double e = thin_line_flow.mm3_per_mm() / 2.40528; // filament_mm/extrusion_mm
 
@@ -371,7 +371,7 @@ namespace Slic3r {
         auto& config = mp_gcodegen.config();
         auto& writer = mp_gcodegen.writer();
 
-        Flow line_flow = Flow(line_width, layer_height, config.nozzle_diameter.get_at(0));
+        Flow line_flow = Flow(line_width, layer_height, m_nozzle_diameter);
         const double filament_area = M_PI * std::pow(config.filament_diameter.value / 2, 2);
         const double e_per_mm = line_flow.mm3_per_mm() / filament_area * config.print_flow_ratio;
 
diff --git a/src/libslic3r/calib.hpp b/src/libslic3r/calib.hpp
index 64edffbeae..aeb99e21e3 100644
--- a/src/libslic3r/calib.hpp
+++ b/src/libslic3r/calib.hpp
@@ -33,6 +33,10 @@ public:
         Horizontal = 0,
         Vertical
     };
+
+    void set_nozzle_diameter() {
+        m_nozzle_diameter = mp_gcodegen->config().nozzle_diameter.get_at(0);
+    }
 private:
     std::string move_to(Vec2d pt, std::string comment = std::string());
     std::string convert_number_to_string(double num);
@@ -44,6 +48,7 @@ private:
 private:
     GCode* mp_gcodegen;
     double m_digit_len {2};
+    double m_nozzle_diameter;
     int m_max_number_length {5};
     double m_number_spacing {3.0};
 }
@@ -82,8 +87,8 @@ class calib_pressure_advance_pattern: public calib_pressure_advance
 
         double to_radians(double degrees) { return degrees * (M_PI / 180); }
         
-        double line_width() { return mp_gcodegen->config().nozzle_diameter.get_at(0) * m_line_ratio / 100; };
-        double line_width_anchor() { return mp_gcodegen->config().nozzle_diameter.get_at(0) * m_anchor_layer_line_ratio / 100; };
+        double line_width() { return m_nozzle_diameter * m_line_ratio / 100; };
+        double line_width_anchor() { return m_nozzle_diameter * m_anchor_layer_line_ratio / 100; };
         
         // from slic3r documentation: spacing = extrusion_width - layer_height * (1 - PI/4)
         double line_spacing() { return line_width() - mp_gcodegen->config().layer_height.value * (1 - M_PI / 4); };