[WJHildreth]

Hey folks!

I am looking for some advice. I started cutting 3D puzzles from 4.75mm lauan plywood. I have been using a 2 flute 1/8" upcut endmill.

What kind of endmill would you recomend cutting this stuff with. I was wondering if a downcut endmill would give me a better finish with less edges to clean up.

What feedrate and pass depth would you recommend? I have been cutting at 20 ipm and .125 pass depth.

Thanks for your help / advice / tips.

As a side note, I was bummed out that I missed out on vetrics advent calendar graphics for Dec 8 and 9. Got busy over the weekend and they slipped my mind. sigh. Maybe I should set an alarm on my phone!!!

Joe

[kazoochips]

Hey WJhildreth,

speeds/feeds are complicated and depend largely on your setup. Your IPM feed speed can vary safely within some percentage depending on how fast your spindle turns in RPMs. If your feed speed is too slow, or you have too many control points in your polylines, your mill will heat up and burn your work piece. If your feed is too fast you will damage your machine or break your mill. But if you're just cutting shallow plywood, there is a fairly broad "safe" range between burn and bust. Google "tooth load" or "end mill speed and feed tooth load" and read some of the thousands or results that will come up from this forum.

On my setup, I'm cutting 1/4 nominal (3/16" or 4.7mm) plywood - birch, lauan, floor underlayment, doesn't matter -- with a 1/8" carbide two-flute mill at up to 80 IPM. that's about as fast as my current mill will go- at this ooint I think I'd have to buy Acme screws to go faster. My cut depth is usually about twice yours (.25") which means it punches all the way through to the spoilboard and a little into that surface on the first (and only) pass. I've heard the rule of thumb that you shouldn't cut deeper on a single pass than the diameter of your endmill, but I'm not having any problems with this setup and I have not broken even a single 1/8" mill yet in tens of thousands of inches of cutting plywood.

My spindle is a Bosch 12-amp 2.25 HP router like this one: [ame=http://www.amazon.com/Bosch-1617EVS-2-1-Variable-Speed-Router/dp/B00004TKHV/ref=sr_1_3?s=hi&ie=UTF8&qid=1355333743&sr=1-3&keywords=bosch+router]Bosch 1617EVS 2-1/4 HP Variable-Speed Router - Amazon.com[/ame]

I usually run it on dial settings between 4 and 6, which corresponds to 20,000 - 25,000 RPM.

I do get a better top surface with down-cut than with up-cut mill, but then I tend to get the same fuzzies on the bottom surface no matter how tight I screw the plywood down to the spoilboard. So I think you're going to have to sand the damn things regardless.

[Larry83301]

Hey folks!

I am looking for some advice. I started cutting 3D puzzles from 4.75mm lauan plywood. I have been using a 2 flute 1/8" upcut endmill.

What kind of endmill would you recomend cutting this stuff with. I was wondering if a downcut endmill would give me a better finish with less edges to clean up.

What feedrate and pass depth would you recommend? I have been cutting at 20 ipm and .125 pass depth.

Thanks for your help / advice / tips.

As a side note, I was bummed out that I missed out on vetrics advent calendar graphics for Dec 8 and 9. Got busy over the weekend and they slipped my mind. sigh. Maybe I should set an alarm on my phone!!!

Joe

Not knowing how solid your table is, I can not tell you feeds and depth, BUT I cut that material full depth at 20" min with an 1/8" cutter like these --- 10 x 1 8" Carbide Micro Drill Bit Router CNC PCB Dremel for PCB Drill Hole 3 175 | eBay --- I cut thru 1/2" 5 ply in two passes with that same type of cutter at that same feed rate. I can cut the 1/4" plywood at 15" min with an 1/16" cutter of that same type. They will cut several hundred inches per cutter, sometimes over a thousand inches before I break one.

Larry

[WJHildreth]

kazoochips,

Thanks for the pointers. I am running a Hitachi Variable Speed router as a spindle on a home build JGRO machine (Now sort of modified away from its original). I set the fed rate at 20 inches as a starting point. I may try to speed it up some, but I am limited by the rigidity of the machine. I plan on making a new one, either thr Kronos KRMx01 or KRMx02, I have not decided.

My first puzzle was from hardboard, YUCK, won't do that again. but while we are on thin plywood, do you have a problem getting the whole piece to lay flat, or are you using more than just screws in the corners to hold it down? I been cutting on pieces cut to 12x16 inches and screwing the corners down, but sometimes I still have a problem with bow, even placing the bow sid down.

When you use a downcut mill at .250 deep pass, do you have a problem with the swarf compacting at the bottom, or does that only matter if you are taking multiple passes?

Again, thanks for the tip, now I am off to search google as per your suggestion.

Joe

[WJHildreth]

Larry,

I think I am going to try a full depth cut the next time I am at the machine.

Thanks for the link.

Joe

[WJHildreth]

Larry,

Those look like roughing bits, can I get away with it using a 2 flute upcut bit?

Joe

[WJHildreth]

Kazoochips,

I you last message you said you would need Acme screws ro go faster. What are you using now?

I am using 3/8-16 threaded rod and delrin cutting board material for anti-backlash nuts. What controller are you using? I use LinuxCNC. Is that your machine in your avatar?

Joe

[kazoochips]

Kazoochips,

I you last message you said you would need Acme screws to go faster. What are you using now?

I am using 3/8-16 threaded rod and delrin cutting board material for anti-backlash nuts. What controller are you using? I use LinuxCNC. Is that your machine in your avatar?

Joe

that's what it looked like before I cut a new z-axis carriage and router mount out of 3/4" maple ply and finally fixed up my dust collection. Suppose I need to post an update to the avatar pic :-D

My drive screws are 13 TPI allthread (5/8" I think? Maybe only 1/2"?) from Home Depot. My machine is based on the "book design" from Buildyourcnc.com - the table and gantry elements were cut out of 3/4" MDF on a table saw and we squared them off and bolted it together in the garage. This is my first venture into CNC milling: it's not super rigid, and I don't have any backlash compensation, but I don't do a whole lot of high-precision small feature work, or any work with metals, so it hasn't been important yet. Using a pen plotter, it is pretty accurate even down to .05" steps. I'm not planning to do any circuit boards so that's probably good enough for me.

The real overall speed killer for me (I think) isn't the top-end speed of the screws, it's the acceleration. I think that's the biggest advantage youget with ballscrews or ACME screws - low friction means better acceleration to your max speeds, which means you can maintain your target feed speed more of the time.

I use LinuxCNC also.

But to answer your other questions- (1) Yeah, thin plywood is warpy. And just hitting the corners usually isn't enough. So when I'm still doing the CAD toolpath layout, I set up a drill MOP before any profile MOPs and I insert drill points for hold-down screws in between the puzzle pieces. That way you can have as many screws as you need to hold your plywood flat. on a 2'x2' square of home depot plywood, I typically screw down the corners and then add six or eight additional screw points between pieces inside the square. I try to choose safe places far enough away from a piece that they won't interfere with the toolpath, and in places where I know that it's going to get floppy if it's not held down (for example, along the long edge of some of those dinosaur tails)

So your machine drills those holes first in safe places using the same 1/8" bit you are going to profile with, and then you pause it or order a tool change and TURN OFF THE ROUTER and then screw the plywood down tight in those safe places, and then you hit 'go' and have it cut out the profiles.

Here's a link to a more current pic of the machine that shows the screws in the middle that I was talking about:

https://www.dropbox.com/s/5sumuvn7rb...2016.55.16.jpg

And (2) at the end of a run, I do have swarf leftover in the channels cut into my spoilboard, but so far that hasn't been a problem. And that's what shopvacs are for, right?

[WJHildreth]

Kazoochips,

I didn't think about doing another set of toolpaths for setting some extra screws. That is a great idea. I think I will start doing that. I have been using tabs to hold in the pieces, normally two or three unless it is a long one. But fighting warp has been one of my bigger challenges. I am definately taking your advice here.

I started building a JGRO in 2006, used it a while then it wen into my outbuilding basement and suffered the wrath of a leak. Had to rebuild the bed and bottom of the gantry, then decided that there wasn't enough support in the X-Axis pipe. I use downloaded the nc files from buildyourcnc and reverse engineered them to get measurments and dimensions from his v1.2 machine. I used his bos slides as a replacement for the pipes on mine. Definite improvement, but should have done the Y and Z axis as well. I want to build a new machine and have been leaning toward the Kronos machines. But if I had a means of working meta, the mechmate looks good too.

Below is a pic of my machine with the boz slides, but before the steel router clamp and cleanup on the wiring.

Joe

[cdrd03]

Here is a link to a post that has the first 8 days from the vectric advent calender.

http://www.cnczone.com/forums/1207220-post2439.html

Chuck

[WJHildreth]

Chuck,

Thanks a bunch!!!! That leaves me only missing day 9!

Thanks again,

Joe

[Larry83301]

Larry,

Those look like roughing bits, can I get away with it using a 2 flute upcut bit?

Joe

Actually they are mostly used for fiberglass. I run them around 25,000 rpm and get a nice finish. If you use an up cut end mill it can throw your part right at the end of the cut. As it’s name implies it brings the chip up and anything else that is loose. A down cut end mill pushes everything down and usually under your work piece. The ones I use do neither as they cut straight.

Larry

[cdrd03]

Sorry I forgot to include that one. here you go

chuck

[Soundcop]

can I get some help on dxf file of a pig / hog silhouette

[WJHildreth]

Chuck,

Thanks a bunch for helping me get caught up. I appreciate it!

Joe

[WJHildreth]

Soundcop,

What kind of help are you looking for. Just looking for a DXF or have something you need converted?

Joe

[WJHildreth]

Soundcop,

Will this work for you?

Joe

[KSerdar]

Hi,

Here is where I purchase my LED Strips. They will custom make them to most any length. They also offer a special mounting system that is taller on the front side which help hide the dots that the LED's make. They offer different wire exit options that can help with your design. They will customize the length of wire and fittings supplied and also offer the required transformer to complete you project. The ones I use are designed to work with 1/4" Plexiglas which actually measures approximately .207 thick. Plexiglas is a formed product and the thickness can vary and effect the outcome of some designs that have minimal DOC requirements.

http://http://www.lumenedge.com/store/index.php


John

I was looking on this web site for the "special mounting system" and could not find it. Do you have the part number or direct link?

Thanks
Ken Serdar

[HelicopterJohn]

Hi Ken,

You will need to call them and tell them you want the edging that is taller on the front side to help hide the LED lights.

You will also need to tell them how you want the wires to exit. I chose out the back side. I think you can also have the wires exit out the end. They have many options so it is best to call them as they may be able to recommend a particular system for your application. They also have multiple colors and even LED strips that can change colors, blink and all kind of crazy stuff. Of course the price goes up for those options. They will also give you a discount if you ask for it.

John

[kiwibrick]

Peugeot Lion logo I used to make centre caps for my wheels
dxf liononly.dxf