After milling, cutting is the second CNC technology DigiFabster has added to its arsenal. We've tried to keep it simple, but will probably add features later on as user requests for additional features start coming in.
This article is meant as a step-by-step guide to set up your first cutter and material. We'll use a generic machine and material, with 2 easy to understand models, to explain the two most basic parts of pricing: time cost and material cost.
To start the setup, go to "Machines and Materials" select the CNC tab, and select CNC Cutter:
In the drop-down "Machine" use "add your machine". This allows you to enter your machine name manually.
We'll be adding more and more preset machines to our database, but for now please set it up by yourself. I've called my machine "cutter" and set up the dimensions:
Travel: there is no travel along the z-axis, but please fill in the maximum thickness of material your machine can handle in the rightmost field. I have entered 25 mm.
Pricing: price per hour.
I've set up a price per hour of $10 for this machine. Since speeds are correlated to material properties and thickness, we'll define those in that section.
All other settings on the machine page I leave alone, they are not needed for the initial setup.
Pricing: Speed and material costs.
As mentioned above, the productivity of a cutter depends on the properties of the material to be cut, and its thickness.
For this example, in which we want to be as transparent as possible, we leave everything empty, except two sample sheets with 2 speeds:
As you can see, the sheet with thickness 5 has a feed rate of 100 cm/hour, the sheet with z=10 has half that feed rate, 50 cm per hour. Those speeds and dimensions were chosen so as to make all further calculations easy to understand.
I don't add the cost of material yet, I first want to test how and if the speed algorithm works.
Testing the speed algorithm
For testing I have created 2 models in STEP format:
These are two squares with a square hole in it, identical but for the z-dimension, which is 5 millimeters or 0.5 centimeters in one case, and 10 millimeters or 1 centimeter in the other. The rest of the dimensions are: 25x25 cm with a cut-out square of 10x10 centimeter. That path of the cutting device can thus be calculated in both cases as:
25+25+25+25 + 10+10+10+10 cm = 140 cm. With a feed rate, as in the case of the 5-millimeter sheet, of 100 cm/hour, one can expect a machine time of 1.4 hours. At a price per hour of $10, this should cost $14. At half the feed rate, as in the case with the 10 millimeter sheet, the cost should be double:
Uploading the samples
To upload your samples for testing, go to your Settings page and copy the URL of your widget:
Enter that URL in your web browser, the widget will appear.
Upload your models by clicking "Add 3D models", wait for them to be uploaded and analyzed, and click next step.
If you created the same samples as I have, the one with the 5 mm thickness should show $14.00:
The one with 10 millimeters should show $28.00:
By adding both to the cart and clicking "proceed to cart" you should get this result:
That seems to work. Now for material pricing.
For now, materials are priced per length, and prices can be entered on the Material page beneath the feed rate we entered earlier:
The 5-mill sheet got a price of $5 per centimeter, the 10-mill sheet had a price of $10. The algorithm will always select fo the smallest stock size possible, so the 5 mill model, which had a cost for cutting of 14, will have an additional material cost of 25 x $5 = $125, bringing the total up to $124+$14=$139, for the 10-mill sheet it will be an additional 10 x $25 = $250, for a total of $250+$28 = $278.
Let's try. Save the new setting, upload the models and check:
The 5-mill sheet gets a price of $139, so that's OK.
The 10-mill sheet gets a price of $278, which means the algorithm is working as expected.
As we've seen, the DigiFabster cutter algorithm takes 2 things
-The total length of the cut, divided by the cutting speed for the selected material and multiplied by the price per hour. The total length of the cut with these samples was 25+25+25+25+10+10+10+10=140 cm, the correct speed gets selected by comparing the thickness of the model with the different thicknesses of available stocked materials and their respective feed rate. In one case that was 100 cm/hour @ $10/hour, thus $14, in the other 50 cm/hour @ $10 per hour, is $28
-The longest side of the bounding box of the model, which gets compared to the price per centimeter length of the selected material. In the cases above it compared 25 cm to a price of $5 and $10/cm and came up with 25 x $5 = $125 for the 5 mill-sample and 25 x $10 =$250 for the 10-mill sample.
This is how the automatically generated invoice looks:
Hope this helps :-)
Your DigiFabster team