Solsylva 25x25 CNC Build Log

[ger21]

I've been pretty happy with Yonico bits from Amazon, like these:
Yonico 31214-SC CNC Router Bit Up Cut Solid Carbide with 1/4-Inch X 3/4-Inch X 1/4-Inch X 2-1/2-Inch 1/4-Inch Shank - - Amazon.com

Very good price, and they seem to be pretty high quality, although they may run a few .001's undersize.

[jlowe1224]

What are you milling? Manufacturer doesn't matter as much as getting the correct type of bit for the job and running it a the proper feed and speed.

Mostly softwood and hardwood, some plastic like HDPE. From what i heard downcuts leave the best finish?

[ger21]

From what i heard downcuts leave the best finish?

It depends on what you're doing. Downcuts will leave a cleaner top edge, and may tear out less than an upcut, but it depends on the specific application and toolpaths.

If I'm cutting parts from hardwoods, I'll usually use a downcut. When I cut dovetails and box joints, I use upcuts.

[jlowe1224]

I was testing how fast i could jog my machine today and i tried 150 in/min which is not nearly as fast as others go, and at random times the x would stall with absolutley no load. Im using 2 start screws so is this at the upper end of the velocity curve where the torque drops drastically? Im using 310 oz unipolar steppers from hobby cnc, and only x stalls like this. I backed down to 120 in/min and it only stalled if i pushed against the x while i ran against it, but i did not have to push hard at all for it to stall. with 2 starts shoul i run it at 100 in/min max? Also when the steppers are powered up i can slightly turn the leadscrews on the x axis before i feel the holding torque of the stepper. It only turns id say 10-20 degrees but i just want to make sure my steppers not damaged because I cant turn the other steppers AT ALL while they are powered. Im a complete noob at this, but learning a ton.

[jlowe1224]

It depends on what you're doing. Downcuts will leave a cleaner top edge, and may tear out less than an upcut, but it depends on the specific application and toolpaths.

If i want to cut profiles all the way through, nothing fancy, on mostly softwoods and hardwoods/plywoods, should i skip the straight flute and just get a 1/4 and 1/8 downcut spiral bit? If im drilling holes i dont want to have to switch out the straight flute because they cant plunge straight down from what i have read.

[wizard]

If i want to cut profiles all the way through, nothing fancy, on mostly softwoods and hardwoods/plywoods, should i skip the straight flute and just get a 1/4 and 1/8 downcut spiral bit? If im drilling holes i dont want to have to switch out the straight flute because they cant plunge straight down from what i have read.

If you want to plunge cut you need cutters that are designed to be center cutting. Cutters are either designed to be center cutting or not, many two flute bits are center cutting.

In some cases you can do pockets (drill holes) with a bit that doesn't center cut if you can follow a helical path into the material. Drill bits are often a far better solution though if you have a lot of holes to drill.

[ger21]

Plunging with a downcut isn't any better than plunging with a straight bit. A downcut pushes the chips down, so when plunging, they don't have anywhere to go. You can get away with it if you do it fast, but there's a very good chance you'll get burned holes.

Also, if you cut all the way through with a downcut, the bottom edge will most likely be a little rough. The spoilboard surface quality will have a bit to do with the bottom edge quality.

[Devastator]

Also when the steppers are powered up i can slightly turn the leadscrews on the x axis before i feel the holding torque of the stepper. It only turns id say 10-20 degrees

Something is loose. Are you using a belt? If so check the tension.

[louieatienza]

Mostly softwood and hardwood, some plastic like HDPE. From what i heard downcuts leave the best finish?

If you want clean edges on both sides and are depth limited per pass try a mortise compression spiral. Upcut to clear chips and leave clean bottom edge when through, with down cut for clean top edge. Although for woods I like single edge spiral O flute tools for 1/4" and under diameter, as they excel at chop clearing.

[louieatienza]

If i want to cut profiles all the way through, nothing fancy, on mostly softwoods and hardwoods/plywoods, should i skip the straight flute and just get a 1/4 and 1/8 downcut spiral bit? If im drilling holes i dont want to have to switch out the straight flute because they cant plunge straight down from what i have read.

Plunging is a great way to test the limits of your Solsylva. Also the bearings on most routers aren't designed for heavy thrust loads. I would use a helix or ramp in strategy for pockets and profiles if possible.

Straight flute is fine, but be aware that hardware store bits are designed for hand-held use and therefore radially depth-limited. This is a safety feature that prevents kickback, but gives less performance and chop clearing.

[jlowe1224]

Something is loose. Are you using a belt? If so check the tension.

Not the belt. I can move the shaft directly, so it has to do with the stepper. I cant feel any steps when i turn it though, so something weird is happening. I just hope it doesnt affect the quality of my cuts

[jlowe1224]

nvm

[jlowe1224]

While waiting on bits, I designed and 3d printed a drag knife. It works pretty well for being 3d printed, the only problem is I need to find a better toolpath generator for it because the cambam plugin one is not quite perfected yet. I have a much better design for drag knife that should be very robust even when 3d printed and it will be very sleek. Ill share the ipt. or stl. files if anyone wants them

[Devastator]

That's pretty cool! I'm slowly building a delta printer of my own design. Might have to hit you up for that file when I'm ready.

I made a drag knife for my machine and it works great on flat stuff, but I made it for use on my rotary axis so I could slot cardboard tubing. It doesn't work right on the rotary axis because my wrap program screws up the tangential code. Made a bunch of scrap and snapped a bunch of blades before I gave up.

[jlowe1224]

That's pretty cool! I'm slowly building a delta printer of my own design. Might have to hit you up for that file when I'm ready.

SeeMeCNC company? Delta printers are IMO the best value printer kits for the size of the print area. I have a reprap that i built a few years ago, and soon want to get an Ultimaker 2 just because they make the best prints ive ever seen

[Devastator]

SeeMeCNC company?

No. Scratch build. Knowing virtually nothing about 3D printers it should be interesting if I can get my dumpster dive delta built well enough to use. I take summers off from all of my basement tinkering projects so i won't start working on it again until fall. It's a big floor unit, not one that sits on a desk. I'm configuring it so I can use it like a traditional 3D printer with plastic, or hook it up to a clay extruder. Like the one at this site: Functional 3D Printed Ceramics - Olivier van Herpt

[jlowe1224]

Let me know if you have any questions! Im way more educated in 3d printers than I am CNC routers, but ive gotten alot better at figuring out cncs. The next thing I need to learn about is different bits and their purposes.

[jlowe1224]

Check out this 20 foot delta 3d printer I saw at a makerfaire last week.

[Devastator]

Let me know if you have any questions! Im way more educated in 3d printers than I am CNC routers, but ive gotten alot better at figuring out cncs. The next thing I need to learn about is different bits and their purposes.

Thanks. I'll hit you up if I get stumped. I'm using NEMA 23's and pibot controller and drivers unless something better comes out before I need them. I almost considered using a Gecko G540 I've had laying around, but decided to keep it in storage for backup.

[jlowe1224]

How big are you planning on making it? NEMA 17's are pretty much the standard 3d printing steppers used. Also I wouldnt run it like a cnc. Grab yourself a RAMPS 1.4 board for $30 Ramps 1 4 Control Board 5 x DRV8825 Stepstick Driver Module for 3D Printer | eBay and it comes with drivers. I use repitier host which is a free slicer/running software which generates the gcode with Cura, and you connect it directly to your board and print from there. It works amazing. Im not sure if RAMPs work with nema 23's, but if I were you id just switch those steppers out. Nema 17s are very cheap.