1. 3+2 Axis Machining and Drilling
On a 3 + 2 Axis Machine it is possible to index the head and\or bed to realign the tool prior to
performing standard X Y Z transitions. This is achieved either by manual adjustment or as
part of the cnc control.
It is possible for customers who do not possess a PowerMILL Multi-Axis licence to create
3+2 strategies by using individual Workplanes to control Tool Alignment and output ncdata
via the NC Preferences form with the Automatic Tool Alignment set to Off.
It is however both faster and easier to create 3 + 2 toolpaths if the Multi-Axis licence is
available as it provides access to a larger range of options with minimal dependency on
individual Workplanes. Either way PowerMILL enables components normally requiring a
series of separate 3-Axis operations to be machined in one set-up. This could include direct
machining of undercut features or sidewalls deeper than the maximum tool length.
It is essential to apply suitable Toolpath – Leads, Links, and Extensions to eliminate any
2. Positional Tool Moves
When performing Positional Tool Moves, it is essential to pay careful attention to preventing
potential collisions and to ensure that the machine tool rotational limits are not exceeded.
Three suggested methods to achieve this include:-
1/ Use of Absolute coordinates in the Start and End Point form.
2/ Insertion of strategically placed Workplanes into an NC Program.
3/ Use of a Pattern Finishing strategy in 3D space.
3. Five Axis Tool Alignment
For 5-Axis applications where the machine tool head and\or table, are required to perform
both linear and rotational axis moves simultaneously, PowerMILL provides a range of
suitable Tool Alignments and Machining Strategies.
5-Axis machining enables components normally requiring a series of 3-Axis operations to be
machined in one set-up. Tools can be re-aligned using 5-Axis control to provide access to the
base of steep or undercut features, which would otherwise inaccessible down the Z-Axis.
In 5-Axis applications, as well as the normal, default gouge checking, a range of options exist
to ensure that no part of the head, spindle or tooling clash with the component between
different strategies. In all cases it is essential to carry out a thorough visual inspection of the
4. Surface Projection Finishing
The strategy is projected along the normals of a single, Reference Surface onto the main
(multi surfaced) component with tool alignment as specified by the user. The toolpath runs
either across or along the Reference Surface directions (U or V) with the Stepover being
defined by unit Distance or Parametric division between Surface Curves. In some cases the
Reference Surface may form part or all, of the component to be machined.
To create a Reference Surface the user will require the services of a suitable Surface
Modeller, ideally PowerSHAPE. For the following example the Reference Surface has
already been created and stored as a separate dgk file to be imported as required
5. Five Axis Pattern Finishing
All strategies with the exception of Plunge Milling and Drilling will directly support 5-Axis
tool alignments. However, certain finishing strategies will only do so where a Ball Nose tool
is being used. For these strategies if an End Mill or Tip Radiused tool is in use a 5-Axis
conversion is achieved by re-machining using the Pattern finishing strategy. If Base
Position – Automatic is specified the toolpath will be recreated to the selected 5-Axis Tool
Alignment (as illustrated below).
6. Embedded Pattern Finishing
This strategy allows the user to produce an Embedded Pattern Finishing Toolpath using an
Embedded Pattern to define the contact points of the toolpath. An Embedded Pattern is a
curve lying on the model linked to its associated surface (or surfaces).
An Embedded Pattern Finishing toolpath can be used to specify the exact position of
contact point or to use information about the underlying surface (for example surface normal)
to determine the Tool Axis orientation when engraving
7. Five Axis Swarf Machining
The Swarf Finishing option creates a toolpath where (by default) the selected surfaces are
machined with the side of the tool (Tool Alignment is automatic). A Swarf Finishing
toolpath will only exist where the tool is able to remain in contact with the surfaces for the
whole cutting depth. This means the surfaces to be machined must be Swarfable (Not
Convex or Concave but Linear relative to an automatic tool alignment). It is possible for the
user to apply a different tool alignment (such as Lead\Lean for deep sidewalls) but the
selected surfaces must still be Swarfable for machining to occur. In cases where imported
surfaces are intended to be Swarfable but are not of a suitable quality, the upper and lower
edges can be created as separate (wireframe) Patterns to be used with Wireframe Swarf
8. Tool Axis Limits
It is possible to set the Toolaxis limits of the machine tool within PowerMILL. This enables
the rotary working envelope to be defined and not exceeded when creating multi-axis
toolpaths. Due to differing configurations between different machine tools the angular limits
are translated in terms of Azimuth and Elevation angles in PowerMILL.
9. Auto Collision Avoidance
Automatic Collision Avoidance can be applied to Vertical alignment operations in cases
where the Shank would otherwise be rubbing on a sidewall and\or the Holder would clash
with the component. If parts of the component still cannot be machined without a tool
collision occurring then these areas will not be included as part of the toolpath.
Note; at present only a limited selection of Finishing strategies support Automatic Collision
Avoidance. These include Constant Z and the 4 Pattern strategies.
10. Machine Tool Simulation
The ability to check for potential Machine Tool – Component collisions is an essential
requirement for Five Axis applications. As a result, PowerMILL contains an additional
Machine Tool toolbar for use with the toolpath Simulation options.
The standard Machine Tool Simulation is purely visual and it is the user’s responsibility to
identify collisions. An additional, ‘cost option’ is available where the Machine Tool
Simulation will stop if a collision situation is identified. At this point a warning box will be
displayed, and once acknowledged (by clicking OK) all moves in a collision condition will
be registered in a list.
The individual component parts of a machine tool (eg; Main Body, Head, Rotary Table,
Cradle, etc) are stored as a set of individual triangle models. These are registered within an
mtd file that controls the orientation and position of the individual triangle models during a
Three basic, multiaxis Machine Tool Simulation (.mtd) files are supplied within the
PowerMILL installation data.
11. Tool Axis Editing
In some applications the type of Tool Alignment option applied to a Five Axis Strategy can
result in unnecessary, exaggerated rotary movements while the cutter runs along a toolpath.
In some cases, these exaggerated movements can result in Tool Holder or Machine Tool
collisions. To reduce this, it is possible to edit the toolpath to have an alternative Tool
Alignment within a user defined, area.
12. Four Axis Rotary Machining
This Finishing strategy is designed for machining a component mounted on a fourth,
programmable Rotary Axis. During milling, the component rotates around the rotational X
axis while the cutter performs simultaneous 3-Axis movements.
13. Hints and Tips
5-Axis Leads and Links
Leads and Links are applied in the same way as for 3-Axis applications and will
automatically take into account the applied 5-Axis – Tool Alignment options .
14. Port Machining
In New strategies the Ports option provides 3 specialist strategies, designed for machining
cylinder head, inlet/outlet ports.
The Port Machining options automatically provide Multi-Axis Tool Alignments where this
is possible. A warning will be displayed if impossible alignment limits are reached and
machining will not occur in these areas.
In New strategies, the Blisks option provides 3 specialist strategies for machining Impellers.
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