Production Routing

In the article Adrian explains how he got into working with CNC and takes us step by step through a recent production job, highlighting areas where he was able to save time and money and along the way throws in a number of useful tips and ideas he finds useful.

Adrian begins by telling us why he decided to start his own CNC business and why he chose to specialize in production routing as opposed to more decorative CNC work.

"Following my career in IT I wanted to start three or four small, primarily home-based, businesses to have multiple income streams to protect myself from any future recessions. One of those businesses was to combine my love of boats and woodworking into a part-time business and do fit-outs of boat interiors, but other than my own boat and a few small jobs that never really took off. It was around this time that I built a small CNC machine to cut the intricate custom pieces needed on a boat.

I learnt a huge amount with that machine and I realized that CNC was something I could really get into as it combined pretty much everything I enjoyed doing. The only thing I found frustrating was the clunky process of creating DXF drawings and generating G-code with the software I was using at the time.

The final piece of the puzzle was coming across to Vectric's VCarve Pro software. It was exactly what I needed; one piece of software that did everything from beginning to end (Adrian has subsequently upgraded to Aspire). I went through the usual route of creating small signs, door plaques, general v-carving etc. before the old business brain kicked in and I realized that sanding and finishing wasn't something that I could automate and consumed an enormous amount of time.

I realized if I really wanted this to be an easy to run part-time business I needed to be able to load materials onto the CNC and literally take the cut items straight off and ship them to the customer.

I decided that producing raw parts for other people to finish was the way to go and I was soon up and running making all sorts of pieces for local businesses and craft people.

There has been plenty of work just through recommendations and repeat business (I've cut over 8,000 of the "twin hearts" so far!) which is just as well as I still haven't got a web presence. This is very embarrassing as I beta test ecommerce software and help develop web strategies for other businesses.

Savings interest rates were pretty dire at the time, so I decided that I could make the money work harder by investing in some new CNC equipment. Due to the limited access to my workshop it had to be a machine that could be assembled on site which really meant a ShopBot. I ordered a PRS Alpha 96x48 (below right) with a 2.2hp spindle and I've been more than happy with it ever since.

Having the larger machine enabled me to move into areas such as radiator cabinets (below left) as well as being able to make more profit on the smaller items by cutting more at a time. Not to mention the massive increase in cutting and movement speed.

When toolpath templates were added to VCarve and Aspire I immediately saw the benefits for what I was doing. Quite a few times I had ruined a sheet of material due to forgetting to add an offset or selecting the wrong tool. The templates gave me a way of ensuring that I was using the correct settings for the job every time without having to go through check lists etc.

I've continued to refine and streamline my processes so that what used to take me hours of toolpathing and setup now only takes a few minutes. I've created a custom interface program for my ShopBot (below center) to save time and reduce errors plus various jigs and fixtures (below right) to make job setup faster and more accurate.

I have huge admiration for people like Tim Merrill (forum user tmerrill) and the 3D work they do. I know I just don't have the patience for the finishing work that is required for pieces like that. Not to mention that I don't have an artistic bone in my body!"

To try and get a more practical understanding of Adrian's process we asked him to describe his most recent job where he had to create six custom MDF boxes to fit into a wall unit the customer already owned. This offers a great insight into his approach to work and more importantly highlights key areas where you can save time. This step by step guide helps reveal how simple and effective production routing can actually be...

"As with 99% of my jobs the customer was to do the final sanding and painting. Just the way I like it!

I did a quick render in Sketchup to make sure that the type of "handle" I was proposing was acceptable. In this case the customer decided that they wanted the handle holes on the back and front. I did this job in Aspire but all the steps I show here apply equally to VCarve and work in exactly the same way.

STEPS:

1. Before I start laying out vectors I load toolpath templates for the types of toolpaths that will be required. I know that a job like this will require a full depth cutout (don't they all!), a series of pockets/dados and something for the handle holes. As I do a two stage toolpath for the final cutting out of the parts I create separate toolpaths for any full depth "interior" cutouts such as the handles.
   You can see from the picture that I have a number of folders for each type of material and thickness that I work with. Within those folders are templates for each type of toolpath I've used in the past.
   
2. I've done several similar boxes in the past (my workshop storage is made up of exactly the same boxes) so I have a master toolpath template already created that has all of the toolpaths in one file. Whenever I do a new job I always save all the toolpaths to a new template file at the end just in case I do it again.
   
3. Once the toolpath is loaded it's important to make sure that the Create Missing Layers option is selected. That way the blank project automatically gets all the correct layers added to it.
   
4. I then start drawing the vectors for the design. I tend to draw out the whole thing and then assign the vectors to the relevant layers once I've finished.
   
   I always design with the XY zero in the centre of the material. This makes placing parts using shortcuts such as Ctrl-Shift-H to copy a piece extremely easy. Once I've finished the layout then I change the XY zero back to my chosen cutting position which is the lower left corner.
   
5. As I used tabs I need to add them in the usual way at this stage using the relevant pre-loaded toolpath. It's important to double check that the Vector Selection is still automatic at this stage. I've found that it can sometimes revert back to Manual when adding tabs.
   
6. Once the design for the basic parts is finished I bring up the layer manager dialog (Ctrl-L), turn off every layer, and then turn each one on in turn making sure that only the vectors I expect are on those layers.
   
7. The next step is to set up for nesting. I tend to group all the vectors that make up a part as sometimes what a human recognizes as vectors that go together isn't the same as what the program sees. In this particular example the vectors will nest perfectly without grouping but I'll go through the steps as though they wouldn't.
   
8. One extra step that I take at this stage is to copy these grouped vectors onto a "backup" layer. You could also save a copy of the file itself at this stage as well. Either way I find it very useful to have the original vectors in a pre-nested state as the nesting can't be undone once you've finished the session.
   
9. Once the nesting has completed the grouped vectors need to be place back onto the correct layers so that the toolpath template can find them. Select all the vectors on the active sheet, right click and choose "Ungroup Objects", "Ungroup back onto original object layers". I repeat this for the other sheets now but it could also be done when you come to generate the toolpaths.
   
10. The final step is to click the 'Recalculate All Toolpaths' icon. The toolpaths automatically select the layers defined in the Vector selection portion of the toolpath definition.
    Working with templates in this way has saved me enormous amounts of time as I no longer forget to place ramps where needed, or which bit works best with which material, or when to use a climb or conventional cut etc.

Apart from setting tabs I never edit a toolpath at all these days.

Not to mention the time savings. I can go from a new session to a ready to run set of toolpaths in well under ten minutes for a job like this knowing that it will cut perfectly first time."

We would like to thank Adrian for sharing his experience in CNC with us and also for helping demonstrate, with the step-by-step example how key features like Toolpath Templates, Layers and Nesting can help save time and money on many jobs.

Tutorials

Below you will find tutorials that help demonstrate how easy it is to utilize features such as Layer Management and Toolpath Templates and Ordering with Vectric's VCarve Pro and Aspire software. You will also find a trial download link for Aspire so you can test the software's deceptively powerful functionality for yourself.

Layer Management

Explains how you can use Layers to keep your work organized and setup efficient modeling and toolpath creation.
(13.5 minutes, 11Mb)

Toolpath Templates and Ordering

Overview of key toolpath features in VCarve Pro and Aspire which can be used to give the user more control over the toolpath and improve productivity when working on similar parts.
(16.5 minutes, 15Mb)