Manufacturing by material removal can often be a simple
process as there are typically only 1 or 2 processes to machine. Take a mould
or die for example. Typically it would initially be machined on a machining
centre to rough and finish the component, on occasions it would be then have to
be spark eroded any areas where small internal corners / sharp internal corners
are necessary. However on large engineered components where it is important the
component does not move in the machining process (especially finishing) it is
important to add further processes into the jobs lifecycle, ie heat treatment,
stress relieving processes, etc.
Starting with a parasolid file, we could use Featureworks to
turn it back into a feature based model, however if you only have SOLIDWORKS
Standard then this function is not available. Also it is of no interest to
change the finished component as this is what the customer requires, the major
issue is that further information needs to be added to the 3d model, to give
instructions on how the machinist should manufacture the part from start to
Here are the following machining steps that maybe followed.
Block up material
- Drill holes and mill scribe lines in aid for
- Saw excess material
- Rough machine for heat treatment
- Rough machine to 5mm all over for stress relieving
- Finish machine (with and without holes)
To build up these stages we are going to work back to front
as we need to work on the finished component and work back to ensure we leave
adequate material on during all the machining processes.
is the initial job, you can see it as just an imported model.
After renaming the default configuration and creating a new
configuration, we can then consider removing the holes the newly create
configuration. A very quick way to remove all the holes is to use the delete
face command, this can be done even though it’s an imported model.
To do this all the faces of the counter-bored hole needs to
be selected (3 on each hole)
This has quickly created 2 configurations, one with ands one
without the holes.
A 3rd configuration is then created ‘machine to 5mm for
stress relieving’, the same process can be used to delete any unwanted fillets.
The next stage is to offset all surfaces by 5mm.
TIP:- If you need to
offset every face, rather than going into the offset surface tool and selecting
every face, is to click on one of the faces and then right click ‘invert
selection’ then re select the face you initially clicked on. After doing this
all the faces are now selected saving a lot of work clicking on each face. Now
we can select the offset surface tool and you will notice that all surface are
selected in the offset parameters box.
Confirming this box will create a surface body that is
offset by 5mm, we can then easily convert this back to a solid by using the
thicken tool and selecting ‘create solid from enclosed volume’.
3 different configurations of the component have now been
created, the next stage is to create a model for rough machining for heat
treatment and so will create a 4th configuration, naming
Cracks can be generated during the heat treatment process so
it is wise to remove any sharp / small internal corner radii. Also it may be
necessary to ultra-sonic test after this process to ensure no cracks have developed,
this means that the shape of the component needs to be very basic with generous
Because the model is built up in reverse, dimensions
relating back to the stress relieving stage can be added ensuring there is
adequate material left on in case of any movement in the material from any
stresses during the machining process.
From there on further configurations can be built to take it all the way back
to the beginning of the jobs life.
Tip:- Once all the
configurations are built, depending on what you call the configuration they are
not going to be in any kind of order. If you put a prefix of Op 1, Op 2, etc
prior to the configuration name they will be listed in the order from the
Initial block right the way through the final component.
By creating configurations for each operation of the job
also gives good visualization of the job at each stage and also gives you the
benefit that you can access the mass of the component after every operation,
which maybe important for lifting and transportation costs if the job has to be
sub contacted out during any stage.
Op1 – Block Up
Op 2 – Drill Holes & Scribe Lines
Op 3 – After Sawing
Op 4 – Machine for Heat Treatment
Op 5 – Machine to +5mm for Stress Relieving
Op 6a – Model Without Holes
Op 6b – Finished Component