diff --git a/cura/Arranging/ShapeArray.py b/cura/Arranging/ShapeArray.py
index 840f9731c2..a063ec30bc 100644
--- a/cura/Arranging/ShapeArray.py
+++ b/cura/Arranging/ShapeArray.py
@@ -3,7 +3,7 @@
 
 import numpy
 import copy
-from typing import Optional, Tuple, TYPE_CHECKING
+from typing import Optional, Tuple, TYPE_CHECKING, Union
 
 from UM.Math.Polygon import Polygon
 
@@ -14,14 +14,14 @@ if TYPE_CHECKING:
 class ShapeArray:
     """Polygon representation as an array for use with :py:class:`cura.Arranging.Arrange.Arrange`"""
 
-    def __init__(self, arr: numpy.array, offset_x: float, offset_y: float, scale: float = 1) -> None:
+    def __init__(self, arr: numpy.ndarray, offset_x: float, offset_y: float, scale: float = 1) -> None:
         self.arr = arr
         self.offset_x = offset_x
         self.offset_y = offset_y
         self.scale = scale
 
     @classmethod
-    def fromPolygon(cls, vertices: numpy.array, scale: float = 1) -> "ShapeArray":
+    def fromPolygon(cls, vertices: numpy.ndarray, scale: float = 1) -> "ShapeArray":
         """Instantiate from a bunch of vertices
 
         :param vertices:
@@ -98,7 +98,7 @@ class ShapeArray:
         return offset_shape_arr, hull_shape_arr
 
     @classmethod
-    def arrayFromPolygon(cls, shape: Tuple[int, int], vertices: numpy.array) -> numpy.array:
+    def arrayFromPolygon(cls, shape: Union[Tuple[int, int], numpy.ndarray], vertices: numpy.ndarray) -> numpy.ndarray:
         """Create :py:class:`numpy.ndarray` with dimensions defined by shape
 
         Fills polygon defined by vertices with ones, all other values zero
@@ -126,7 +126,7 @@ class ShapeArray:
         return base_array
 
     @classmethod
-    def _check(cls, p1: numpy.array, p2: numpy.array, base_array: numpy.array) -> Optional[numpy.array]:
+    def _check(cls, p1: numpy.ndarray, p2: numpy.ndarray, base_array: numpy.ndarray) -> Optional[numpy.ndarray]:
         """Return indices that mark one side of the line, used by arrayFromPolygon
 
         Uses the line defined by p1 and p2 to check array of
diff --git a/cura/LayerPolygon.py b/cura/LayerPolygon.py
index 6e518e984a..7f62a0a8fa 100644
--- a/cura/LayerPolygon.py
+++ b/cura/LayerPolygon.py
@@ -65,7 +65,7 @@ class LayerPolygon:
 
         # When type is used as index returns true if type == LayerPolygon.InfillType or type == LayerPolygon.SkinType or type == LayerPolygon.SupportInfillType
         # Should be generated in better way, not hardcoded.
-        self._is_infill_or_skin_type_map = numpy.array([0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0], dtype = numpy.bool)
+        self._is_infill_or_skin_type_map = numpy.array([0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0], dtype = bool)
 
         self._build_cache_line_mesh_mask = None  # type: Optional[numpy.ndarray]
         self._build_cache_needed_points = None  # type: Optional[numpy.ndarray]
@@ -73,18 +73,17 @@ class LayerPolygon:
     def buildCache(self) -> None:
         # For the line mesh we do not draw Infill or Jumps. Therefore those lines are filtered out.
         self._build_cache_line_mesh_mask = numpy.ones(self._jump_mask.shape, dtype = bool)
-        mesh_line_count = numpy.sum(self._build_cache_line_mesh_mask)
         self._index_begin = 0
-        self._index_end = mesh_line_count
+        self._index_end = cast(int, numpy.sum(self._build_cache_line_mesh_mask))
 
-        self._build_cache_needed_points = numpy.ones((len(self._types), 2), dtype = numpy.bool)
+        self._build_cache_needed_points = numpy.ones((len(self._types), 2), dtype = bool)
         # Only if the type of line segment changes do we need to add an extra vertex to change colors
         self._build_cache_needed_points[1:, 0][:, numpy.newaxis] = self._types[1:] != self._types[:-1]
         # Mark points as unneeded if they are of types we don't want in the line mesh according to the calculated mask
         numpy.logical_and(self._build_cache_needed_points, self._build_cache_line_mesh_mask, self._build_cache_needed_points )
 
         self._vertex_begin = 0
-        self._vertex_end = numpy.sum( self._build_cache_needed_points )
+        self._vertex_end = cast(int, numpy.sum(self._build_cache_needed_points))
 
     def build(self, vertex_offset: int, index_offset: int, vertices: numpy.ndarray, colors: numpy.ndarray, line_dimensions: numpy.ndarray, feedrates: numpy.ndarray, extruders: numpy.ndarray, line_types: numpy.ndarray, indices: numpy.ndarray) -> None:
         """Set all the arrays provided by the function caller, representing the LayerPolygon
diff --git a/cura/Snapshot.py b/cura/Snapshot.py
index bc7da4080a..ca9c442fb5 100644
--- a/cura/Snapshot.py
+++ b/cura/Snapshot.py
@@ -25,8 +25,8 @@ class Snapshot:
         pixels = numpy.frombuffer(pixel_array, dtype=numpy.uint8).reshape([height, width, 4])
         # Find indices of non zero pixels
         nonzero_pixels = numpy.nonzero(pixels)
-        min_y, min_x, min_a_ = numpy.amin(nonzero_pixels, axis=1)
-        max_y, max_x, max_a_ = numpy.amax(nonzero_pixels, axis=1)
+        min_y, min_x, min_a_ = numpy.amin(nonzero_pixels, axis=1)  # type: ignore
+        max_y, max_x, max_a_ = numpy.amax(nonzero_pixels, axis=1)  # type: ignore
 
         return min_x, max_x, min_y, max_y