Entering new tools into tool Data Base V CarvePro

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momojito
Posts: 39
Joined: Fri Jan 27, 2012 11:35 pm
Location: Fort Myers, Florida

Entering new tools into tool Data Base V CarvePro

Post by momojito »

Hi I am new to this. I am trying to enter some new bits into the tool Data Base of V CarvePro and have no idea what information to put in.

The Bites I am trying to enter are:
0.0625in. (1.59 mm) PreciseBit 2-flute Ball-nose End-mill, 0.200 in. max DOC, 1.5 in. OAL
0.1250 in. (3.18 mm) PreciseBit 2-flute Ball-nose End-mill, 0.50 in. max DOC, 1.5 in. OAL
0.2498 in, (6.35 mm) dia. 4-flute 0° Tapered Ball-nose Carving bit, 1.00 in. DOC, 1/4 in. shank, 2.5 in. OAL


Geometry
Diameter (D) ??? (My guess is this is the shank size 1/4" 1/8")

Cutting Parameters
Pass Depth ??? (No Idea what this is)
Step Over ??? (No Idea what this is)

Feeds & Speeds
Spindle Speed ??? (Speed of the Router)
Feed Rate ??? (My guess is this is the speed of XY&Z)
Plunge Rate ??? (No Idea what this is)
Would appreciate if someone could help me with this.
Thanks
Bruce

saramos
Posts: 83
Joined: Sun Apr 24, 2011 1:27 pm
Location: Nortridge, CA

Re: Entering new tools into tool Data Base V CarvePro

Post by saramos »

Here's a general description of the various parameters. What values to use can vary based on the material of the bit and the material the bit is being used on.
Geometry
Diameter (D) is the diameter of the cutting tip of the bit such as the .0625, .125 and .2498 for the bits you listed.

Cutting Parameters
Pass depth
This is the maximum depth that the cutter will make in a single pass. This will depend on the material being cut. You can take deeper cuts in wood than acrylic or aluminum. A general rule of thumb for wood is for it to be no more than the diameter of the bit.
Step Over
This is the distance that the cutter will move over on the next pass. For instance, a stepover of 25% on a 1" mill end means that when clearing a 2" area, the bit will overlap 75% of the last pass. This means that the 1" mill end will take a total of 5 passes to cover a 2" wide cut. The first cut is the full diameter of the bit, and then it will move .25" over for the next 4 passes to make the total width of the 2" cut. Again, the value used is dependent on the material being cut, and the quality of the finished cut desired. Ball nose bits are used for doing 3D cutting. The fineness of the cut depends on not just the diameter of the ball end, but also on the amount of overlap on each pass. The smaller the stepover, the finer the result. You may want to do rough cutting with a large stepover, and the final pass with a small stepover in a project using a rough cut and a final cut.

Feeds & Speeds
Spindle Speed
This is the speed (RPM) at which the bit is designed to spin when cutting a given material.
Feed rate
This is the speed in in/sec or mm/sec at which the router moves over the work for this bit in a given material.
Plunge rate
This is the speed in in/sec or mm/sec that the router will plunge into the material. Again this is dependent on the material being cut and type of bit.

Determining the proper spindle speed, feed rate and plunge rate can be fairly complicated in order to get a good cut. Also, the spindle speed can affect the proper feed rate and plunge rate. In order for the bit to properly work, each cutting flute should remove a certain amount of material, called the chip size. The proper chip size is achieved by a balance of the spindle speed and the feed rate (this is called the speed & feed for a given bit cutting a given material).
If the speed and feed is too slow, you generate dust instead of chips and it generates more heat friction which can burn the material, and will cause pre-mature wear on the bit. If the speed and feed is too fast, you can cause chatter giving a rougher cut, possibly cause the CNC machine to loose it's proper x, y and z coordinates, and even break your bit. Given two end mills of the same size, one with 2 flutes, and 1 with 4 flutes, you will use a slower speed and feed with the 2 flute bit than the 4 flute bit to achieve the same chip size. Speed and feed also affects how smooth the resulting cut is with slower producing a smother cut, and faster producing a rougher cut.
Also affecting the speed and feed settings is the size of the bits. Generally, the smaller the bits, the slower the speeds and feeds you will need.

For selecting the proper parameters it's best to get advice from more experienced users. You can also often check with the manufacturer of the bits as they will often provide suggested speeds and feeds for their bits. Also, there are some applications you can find that will calculate the suggested speeds and feeds when you enter the various variables such as cutter type, cutter material, material being cut and so forth.

Hope this gives you an idea as to what the parameters are and what they mean.

Scott

momojito
Posts: 39
Joined: Fri Jan 27, 2012 11:35 pm
Location: Fort Myers, Florida

Re: Entering new tools into tool Data Base V CarvePro

Post by momojito »

I am still a little confused on the settings. If it will help my machine is a Shark Pro with a Bosch Colt Router. I also posted this ? in the Vectric Forum. I would like to hear some other answers to the settings based on the information given. I am new to CNC and find it hard to understand these settings so Please bare with me.
Seems to be a different answer for the Geometry Diameter (D) and could use some clarification on the other settings. I am posting the answer from the Vectric Forum hoping that will help me to better understand.
Thanks
Bruce


Diameter is the shank size as you've guessed.

Pass depth is the maximum depth the bit will go into the material on each pass. If you set it to 1/4" and you're cutting 1" deep then it will takes four passes to cut. What you set this to depends on what type of machine you have etc. A rule of thumb is to set it equal to the diameter (shank) of the bit to start with but even that can be too much for some lighter machines.

Step over is how far the machine moves over between horizontal passes such as a pocket or VCarve toolpath. Again a lot depends on the machine and what you want to achieve but 10% is typical for a ball nose whereas 40% would be better for an end mill.

Spindle speed is the RPM of your router or spindle. Only used if your control software can control the speed of the router.

Feed rate is the XY movement speed. You need to work out a the start point for this using chip load tables and/or information from the makers of the bits and/or people with similiar machines to yours. It varies enormously depending on what type of material you're cutting as well as the power of your machine.

Plunge rate is the Z movement speed. Same caveats as above.

Eagle55
Posts: 788
Joined: Sun Nov 20, 2011 8:44 pm

Re: Entering new tools into tool Data Base V CarvePro

Post by Eagle55 »

I'm probably not the best one to answer the questions you have but I know sometimes it can be difficult to get the specific answers you are looking for. Bottom line is that a lot of the bit parameters has to do with the material you are cutting, how fast you prefer to cut it and the size and strength of the bit and the machine. Keep in mind the whole time that the software was not written for just the Shark machines, but rather the "CNC world" so you have to understand some of the things that are said with this in mind.

Starting with the easiest of the settings: Spindle speed ~ The Shark machines don't have software controlled spindles but rather a fixed speed router. This setting does nothing because you are controlling the speed of your router by the adjustment on the routher.

Geometry ~ Equally easy The diameter that this needs to be is the diameter of the cutting tool (not the diameter of the shank as one answer you were given. This is what the software uses to determine the calculations and moves to make and needs to be correct if you expect your computer renderings from the program to match what is actually carved. If you use an 1/8" ball nose bit with a 1/4" shank, you are going to put .125 or 1/8" for the diameter.

Pass Depth ~ as stated in other answers, this is the depth at which the machine is going to cut on one pass. If you have a depth of .125 pass depth and you are going to cut a pattern that had depth of .25" then it is going to calculate two passes to complete the cutting. This is important because it can increase or decrease the stress on the bit and the machine. Although the machine may be able to cut a .25" pass depth at 100 in/min, it is not always wise to do this. Personally I probably cut slower than most Shark users because along with less stress on the gantry and overall machine design comes, more accurate cutting, less cleanup and sanding and longer tool life. I use the default settings of comparable tools and cut it in half until I determine that I can go faster. For the 1/8 ball nose I would use a 1/8" pass depth and probably the same or less for the 1/16" ball nose. Another stress relieving factor is the step over setting.

Stepover setting ~ This is the amount of over lap that a cutter will have from the previous pass. Its been explained accurately as to what it is, but I sense you are wanting to know what numbers to put in, not just the description of what it is. Example, if you are using a bigger diameter (say 1/4" ball nose) to do a roughing pass on a 3d carving, I would use somewhere between 30%-40% You can live with the trashy rough cuts that this high of setting will produce because you just removing the bulk of the material and are going to have a finishing pass that will smooth it up. On your finishing pass using a smaller diameter cutter (say 1/8" ball nose) you would use maybe 5%-15% so that there is less material removed with each pass and the results are much more finished and smooth with fewer tool marks to have to sand or smooth.

Feed rates ~ I think the general default for the tools that you listed would normally be 100 in/min (exception being the 1/16" ball nose) I'm sure some others would join me and say that you don't need to cut anything at this speed unless your material was super soft and resulting smoothness and remaining clean up to the carving wasn't important. Personally I have designed projects using that as the rate of feed but then reduce it to 30-50% speed on the actual control panel slider when I went to cut the job. There again, keeping accuracy robbing stress on the machine to a minimum as well as cleaner cutting, which brings along with it less sanding. I know the machine can handle faster feed rates than I put to it, but there is something that just feels wrong when a machine is "jerking around" and the rpm has drastic variances as it cuts through the pattern or lettering. I haven't had experience much with the 1/16" ball nose but my guess would be that the feed for this would need to be around 40 in/min and even then being used for a finishing pass where the stepover is somewhere around 10% or less. Its gonna be easy to burn up or break a 1/16" bit.

Plunge rate ~ I use 15-20 in/min This is less heating on the tool during the initial plunge into the material and is actually used a very small amount of the time. My theory is don't heat the tool edges up any more than necessary. The bigger the tool diameter, hence the more material being removed dictates an even slower plunge and feed rates.

Maybe this will help some, and hopefully some more experienced carvers will speak up too.

Roger
CNC Shark HD ~ Control Panel 2.0 ~ Windows 7 & XP
Located in West Tennessee near the Tennessee River
http://www.eaglecarver4.com

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