Newbie here needs help

[B_Linder_UCWP]

Hey guys my name is Brian and a cabinet builder in Greenville SC. I recently purchased a PRS Alpha 48 96 and attended the training class at Shopbot. I have had this tool for over a month and just learning my way around everything but I have to admit....when I started I had no idea what I was doing....I am learning now for sure but I have tons of questions and doing tons of research. I look forward to learning from you and my apologies in advance if I ask some stupid questions.

[Rob Gunn]

My old boss always told me "No stupid questions, only stupid mistakes"...
I learned a lot with YouTube videos, Shopbot and Vectric.
Use up all your scrap wood laying around the shop making test cuts. You will make mistakes but will learn from them.

[chiloquinruss]

I have a secret and that is I am a model maker, that is why I bought a Bot. However I have made lots of other stuff, furniture, signs, mantles, etc,. What I have discovered is if I have a pending BIG project I can make a model of it to see if the concept works, if it does then its on to the full size EXPENSIVE stuff! :D Russ

[phil_o]

If you are using Aspire or V-Carve I suggest you go to the Vectric forum too. There's a lot of good help there.

Phil

[coryatjohn]

>> ...but I have tons of questions

The first step in that journey is to ask a question.

[B_Linder_UCWP]

Thanks guys! I am on it and have already drawn my first 2 projects and cut one of them Friday. I also made a flattening file for some walnut trays I am going to make and my new surfacing bit is burning the wood on the pass.
Tool Amana 45566
18000 RPM
50 in/min.
Can I change the feed and speed rates on the toolpath itself or go into the tool data base and change it? When changing feeds and speeds whats a good rule of thumb to go by? How much faster or slower should I go to get a better result? Do I increase the RPM's and the move speed or just one at a time?

[coryatjohn]

Personally, I keep the RPM's down to about 12k or less with big bits. Speed you're running is a bit high too. Again, I keep the speed to about 6"/sec. Going fast with a SB tends to cause deflection errors to increase.

You can easily change the feeds/speeds in the toolpath file yourself if you're comfortable editing the file, or just go back and regenerate a new toolpath file with changes to feeds/speeds.

I suggest taking a bunch of scraps and cutting them into dust. The best way to learn is to try different things. You'll learn a lot by cutting up a lot of worthless wood and probably break a few bits too. It's the best way to dive in. Once you start getting a feel for the machine, and a lot of it is actually "feel" in the form of sounds and vibrations emanating from the machine, you'll be able to guess at the right feeds/speeds.

My personal starting point is 6 ips and 1/4 of the bit diameter for depth of cut and stepover. Adjust from there for the specific endmill and job.

[jTr]

For an accurate answer, a very important piece of information is needed:

How much material are you trying to remove in a single pass?
That effects the rest of your cutting parameters.

When surfacing lumber as you describe, I'm running a 1.5" surfacer at 3-4 ips (180 - 240 ipm), 12k rpm and absolute max of .125" depth of cut to start clipping off the highest spots of a slab of very rough lumber. Once your bit remains in contact with the workpiece for 50+% of the surfacing cycle, reduce depth of cut to .06 or less for optimal finish and reduced strain on your motor.
Also worth noting, this is my experience with a 2.2HP spindle. Can't comment on router if that's your motor, but certainly seems logical a higher HP spindle may handle a more aggressive pace.

FWIW, In 7 years of professional use, average feed and speed rate range is 3- 5 ips (180 - 300 ipm), 10-12k rpm. Sounds like you're being overly cautious with exceedingly low feed rate, causing the burning issue.

As for altering feed/speed settings, this can be done directly in your tool database, or hit the EDIT button in tool selection part of VCPro toolpath generation to alter to suit the job at hand. Disappointing to hear your SB training did not include this routine part of generating toolpaths, but perhaps they don't get into that topic in training?

We appreciate your enthusiasm - keep cutting and the picture will become clearer!

jeff

[B_Linder_UCWP]

Thanks guys, I am removing .03 per pass and I think the move speed is too slow...I will adjust it and keep moving forward. The training class went over the speeds and feeds but I was completely over whelmed with everything going on so I couldn't remember how to change them. I'll keep at it and keep learning. I spent about 5 hrs today watching Youtube videos on Vectric and trying new drawing techniques....
Thanks again,
Brian

[chiloquinruss]

While running the SB software using the < or > key will speed up the feed or slow it down. Router or spindle speed should be set before running the job. My much older Bot has a manual speed controller for the spindle so I can cheat a little. To fast a speed and the bits no longer make chips, just dust and sometimes smoke! ;) You always want to make chips. If everything is set correctly you get clean cuts, the bit stays cooler and just the chips are warm. Have fun. Russ