How much should my pass depth be?

[nick]

Hi all...I'm a new botter and have cutting questions...

What determines the pass depth? speed / quality / material...or is their a rule of no greater than a value...eg .125?

How to experienced botters properly choose bits...

Is their a rule for when to use straight bits, up cut bits, down cut bits, end mills? my material is up to 1" Soft and hard woods.

When doing signs, lettering, 3D graphics...does the cutting edge diameter for ballnose bits effect the detail...I'm sure it does to a certain degree...I'm using the 1/8" tapered ball nose now on some 3D cutting from the starter kit and want to know what the rule of thumb is with CED...What a 1/4 diameter bit yield better results than a 1/8 diameter.

Thanks Guys

Nick Corso

[ron_varela]

Nick all good questions but hard to answer.
The type of work you will be trying to do will determine the bit you should use.
Ball nose bits are used mostly for letters and 3d engraving, you will get better detail from a 1/8 than a ¼ bit but again this depends on the file you are cutting and the stepover.
If you have the starter kit bits then you are off to a good start but in the next few months you will need other bits to do the job at hand.
To save you time and money post what you are trying to accomplish and you will get better answers to your questions.

What determines the pass depth.

You decide this, if you are cutting into or thru 1 inch material you would want it to cut in 2 or more passes depending on your machine and the speed you set to cut it.
Hard material like Oak should be cut in more passes and using a sharp bit, I prefer diamond bits for cutting oak.


Is their a rule for when to use straight bits, up cut bits, down cut bits, end mills

Upcut

7402

Down Cut

7403


When doing signs, lettering, 3D graphics

Any sign and letter can be done with Ball nose End Mill and V Bits, use larger diameter bits to remove waste material and smaller diameter bits for detail.
The strategy is to use the bits to save you time and get the best results.

When doing 3d work you will find using more then 1 bit will result in better detail.

Ron

[knight_toolworks]

cut depth depends on many things. your machine and how ridged it is and how well you have the part secured. it depends on the bits size. A general rule is not to cut twice the bit depth in a single pass but that depends on what your cutting. the hardness of the material is another. the harder it is the shallower the passes need to be. but that depends on bit size too. a smaller bit needs shallower passes to keep from breaking.

[jsfrost]

In addition to the good advice above, here's a few other things to consider:

Bit size is often a compromise of cut time VS detail. 3D with a 1/4 bit will cut roughly 4 times faster than with a 1/8th, but, as mentioned above, with less detail. If the source material lacks detail, there may be no advantage to the smaller bit. If the finished piece is large the loss of detail may be very slight.

Using deeper cuts, especially at higher speeds trade off cut quality for lower cut time. In choosing the right bit you need to ballance your taste, the project needs, and the customer's willingness to pay more for better quality. In some markets, perfect work at higher prices is the wrong answer. Really bad work is always the wrong answer.

Guidelines are just that, guidelines. Let your taste and your customer's goals influence your toolpath choices. With experience most of your choices will work out. And, in your pricing, realize there will always be a scrap bin.

[knight_toolworks]

I find on 3d as long as the bit is long enough I don't worry about pass depth. since your taking off so little. the last one I did with a 1/8" bit was 1/2" deep I did it at 3ips but I cranked the z to 3 that really helped in speed. I did it in a single pass with no problems.

[nick]

Hi guys....thank you all so much...I have taken all your input and recommendations and have a lot of experimenting to do. Will report my progress soon...

thanks