Cut Quality Test Results - Input Appreciated

Talk about all things CNC
XStroX
Posts: 27
Joined: Mon Mar 02, 2015 12:30 am

Cut Quality Test Results - Input Appreciated

Post by XStroX » Sat Feb 13, 2016 3:12 am

I've been getting sick of all the sanding I need to do after cutting projects out with my Shapeoko 3. I don't feel like I hear others complaining about this that often and figured I must be doing something wrong. I decided to run a number of test cuts. See below. All are with DWP611 and the material is Kiln-Dried Aspen from Lowes.
Capture.JPG
Capture.JPG (293.68 KiB) Viewed 1010 times
Based on above, it would seem most of my problems come from using the older endmill vs. the new endmill. With the new square endmill, it also seems as though 60 in/min cut better than 20 in/min. I"m not seeing a major difference based on depth of cut, direction of cut or speed. I did notice from a hearing standpoint, only 0.02 didn't sound awful but I don't see that showing up in the cut quality and certainly won't be cutting at 0.02 depth due to time.

Question for you all: How quickly do endmills go dull? How many hours of cutting? Is there a particular end mill that should cut through Aspen like butter? I need something with a square or close to square end.

Thanks everyone!

Atonwa
Posts: 238
Joined: Tue Dec 30, 2014 2:54 pm
Location: Corning, NY

Re: Cut Quality Test Results - Input Appreciated

Post by Atonwa » Sat Feb 13, 2016 3:57 am

From looking at your cuts and reading up on Aspen it looks like a pretty soft hardwood. I've never worked with it but if I was getting cuts like that I would try a downward two flute cutter and see if that helps with the cut.

As far as when end mills go dull all depends on the quality of the tooling and how abrasive the material your cutting is. High quality carbide should stay sharp for a long time while cutting wood. Other than the endmills I've used in stone I don't have any that I would deem dull yet.

If your using Chinese tooling it may be a different story. The consistency of that tooling usually is not as good so you may have some soft or brittle bits in the bunch that may dull quicker than others.

Also I rarely have a perfect cut that does not require a light sand on the top surface to remove burrs when working in anything other than hard maple.
Shapeoko 3 #109
Routakit HD Beta #001

TomDChi
Posts: 184
Joined: Wed Mar 18, 2015 2:36 pm

Re: Cut Quality Test Results - Input Appreciated

Post by TomDChi » Sat Feb 13, 2016 4:03 am

I've been using a downcut 2 flute spiral mill in wood and have been getting very clean cuts. You need to think about about how it's packing the sawdust down particularly when slotting (so you have to limit the depth of each slotting pass), but otherwise they've been great. I've been using the Onsrud downcuts for wood, but I'm sure there are comparably good end mills which are probably less expensive.

XStroX
Posts: 27
Joined: Mon Mar 02, 2015 12:30 am

Re: Cut Quality Test Results - Input Appreciated

Post by XStroX » Sat Feb 13, 2016 4:55 am

The bits I have been using are from drillman1 on Ebay which I've heard are excellent. All are carbide. I have not however used a downward spiral so I just ordered one to give it a shot.

Also, you mentioned you get a cleanest cut with maple? If so I'll have to pick up a few pieces and give it a shot. The edge glued Aspen boards are just very cheap but it would be worth a cleaner cut to pay more for maple.

I'm for just about anything right now that eliminates the 3 hours I spend sanding my latest piece. There are lots of steps in the piece which equals thousands of the wood spiral remnants showing in most of the above picture.

XStroX
Posts: 27
Joined: Mon Mar 02, 2015 12:30 am

Re: Cut Quality Test Results - Input Appreciated

Post by XStroX » Sat Feb 13, 2016 5:03 am

And thank you both for responding!!!

Atonwa
Posts: 238
Joined: Tue Dec 30, 2014 2:54 pm
Location: Corning, NY

Re: Cut Quality Test Results - Input Appreciated

Post by Atonwa » Sat Feb 13, 2016 5:08 am

I also use the Drillman1 bits and have no issues so that points toward the wood.

The type of maple is sugar or hard maple. It's so hard and dense it basically cuts like metal. I bought out a wood shop that closed in my area so I have no idea what the going price is for it but I imagine it won't be cheap. Another option may be oak.
Shapeoko 3 #109
Routakit HD Beta #001

DRobs86
Posts: 148
Joined: Fri Jun 05, 2015 4:19 am

Re: Cut Quality Test Results - Input Appreciated

Post by DRobs86 » Sat Feb 13, 2016 5:14 am

I will throw another vote in for the downcut. Like you, I spend a lot of time cleaning things up before they looked perfect. With a downcut they come off the mill close to perfect.

EDIT:

This is with baltic birch ply.

Estlcam
Posts: 89
Joined: Tue Sep 10, 2013 3:13 pm
Location: Germany
Contact:

Re: Cut Quality Test Results - Input Appreciated

Post by Estlcam » Sat Feb 13, 2016 9:44 am

For wood there are 2 important factors to consider:
  • Sharpness:
    • As you've already noticed new tools cut better than old ones.
    • it its sometimes worth getting a more expensive tool - the differences in sharpness and endurance can be significant and compensate the additional cost.
    • Don't mix tools: e.g. a tool used for aluminum should not be used for wood - the aluminum residues blunt the cutting edges and increase friction.
  • Flute:
    • Wood tools usually have a straight, neutral flute.
    • Spiral flutes try to lift the material - catch a wood grain, pull it up and create the messy edges you've observed.
    • Downward cutting tools do the opposite: they compress the material which improves the result. But: they also create major headaches for deep cuts.
It is important to choose the right tool - a tool for steel or aluminum is not well suited for wood.
Estlcam CAM and Arduino UNO CNC controller: www.estlcam.com

Shook
Posts: 139
Joined: Thu Nov 12, 2015 6:50 pm
Location: Downingtown, PA

Re: Cut Quality Test Results - Input Appreciated

Post by Shook » Sat Feb 13, 2016 11:12 pm

I'm in the "blame the wood" camp. I've been cutting mostly pine and red oak (home depot's wide selection).

I have a ton of pine because my kids both take Tae Kwon Do and do a fair bit of board breaking. This leaves me with 1x12 pine in widths from 2-5 inches depending on where it started out and how it broke.
(BTW - if anyone has some project ideas for these scraps, I'm all ears)

The pine has a ton of tear out problems with 2 flute cutters from Drillman, but the oak comes out perfectly. This isn't just a problem with power tools, I've had the same experience with hand tools and pine. It's really brittle and has a tendency to splinter out instead of making a clean cut.
Shapeoko 3 (#1107)

WillAdams
Posts: 8528
Joined: Mon Apr 09, 2012 6:11 pm
Location: Pennsylvania --- south of the Turnpike, East of US-15
Contact:

Re: Cut Quality Test Results - Input Appreciated

Post by WillAdams » Sat Feb 13, 2016 11:58 pm

White pine, which is very soft, wants a very sharp tool, and an awareness of grain direction when cutting.

My inclination for the scraps would be to cut finger joints into them and use them pieced together for projects which they’d be suitable for.
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
Nomad 883 Pro #596 (bamboo)

Post Reply