Raster

Use the Raster page to specify the segment order and control the angle of the cutting moves. You can specify the angle of the roughing pass manually or automatically. The available options page are dependent on the selected strategy:

Fixed direction — Select to enable the Angle option. When deselected, PowerMill automatically determines the most suitable angle for each area in turn.

• Angle — Manually specify the angle for all raster passes. The angle is measured counter-clockwise around the Z axis of the active workplane, where an angle of 0 lies parallel to the X axis.

Cut direction — Select a milling style for Profile and Area.

• Climb — Select to create toolpaths using only climb milling, where possible. The tool is on the left of the machined edge when viewed in the direction of tool travel.

  

• Conventional — Select to create toolpaths using only conventional or upcut milling, where possible. The tool is on the right of the machined edge when viewed in the direction of tool travel.

  

• Any — Select to create toolpaths using both conventional and climb milling. This minimises the tool lifts and tool travel.

Minimise full width cuts — Select to remove (as far as is possible) all raster moves that could cause the tool to cut on its full width. Due to the searching nature of the raster pattern, the tool may occasionally be cutting on its full width. This is not generally a problem when cutting soft material, but can cause tool damage when machining hard material.

Machine all raster spans — Select to machine all raster spans. When deselected, unnecessary raster spans are left unmachined. For high speed machining, it is best to have this option selected to ensure an even loading on the tool. An unnecessary raster span is one where the tool either doesn't remove any material or doesn't remove any material that a future pass would not remove. This can happen on the first and possibly the last raster span of an area, and where the raster spans are shorter than the diameter of the tool.

Maintain constant stepover — Select to ensurethe stepover within an area remains constant (so that cutter passes lie on both edges of each area).

When — Select when profile moves are performed in relation to the area cutter moves.

• None — Selecting this option machines the first offset profile, then moves inwards to clear the remaining area. The workpiece profile is not machined.
• Before — When selected, the tool profiles the workpiece first and then moves inwards to clear the remaining area. This involves two cutter moves with associated rapid and level moves.
• During — When selected, PowerMill automatically chooses to apply the behaviour of the Before or After options depending on the position of the outer profile relative to the block boundary. If the outer profile lies entirely on the block boundary, PowerMill uses the Before option. If any part of the outer profile touches the workpiece, PowerMill uses the After option. There is no Z lift between area clearance and profile moves.
• After — Selecting this option machines the innermost profile first, then moves outwards to clear the area, then finally machines the workpiece profile. This also involves two cutter moves with associated rapid and level moves.

Feature face milling

The following options are unique to the Raster page for feature face milling strategies:

Style — Select the toolpath segment order.

• One Way — All the passes, except for the last one, are in the same direction. The last pass is in the opposite direction. This helps to produce a clean surface. If the last pass is in the same direction as the other passes, then it may leave burrs on the edge as the material is pushed outwards.
• Two Way — Passes are in alternate directions.
• Spiral — The passes start at the outside of the block and work towards the middle.
• One Pass — A single pass is generated, just off the centre of the block. This is useful for facing a block which is smaller than the tool diameter. The pass is off-centre to avoid excessive tool wear by effectively avoiding machining small slivers.

Approach type — Select the approach move used when the tool starts to cut.

• Straight — The tool moves straight into the cut.

  

• Roll-in — The tool makes an arc move to roll into the cut. The diameter of the arc is the tool diameter plus a suitable tolerance. This approach method can reduce the chip size of removed material.

  

Steep and shallow finishing

The following options are unique to the Raster page for steep and shallow finishing strategies:

Perpendicular pass —Select to define a second raster pass perpendicular to the first one.

Shallow angle — Enter an angle to specify that the raster pass machines only the areas of the model that are steeper than this angle.

Optimise parallel pass — If a raster toolpath is created with a parallel and perpendicular pass, and with a shallow angle greater than 0, select this option to trim the parallel pass so it does not machine the areas that the perpendicular pass machines.

Wall clearance —Enter the clearance to be used to prevent raster spans at the bottom of a steep area from hitting that steep area. This prevents dwell marks on the steep areas.