What’s the depth of cut and width of cut too.

I’m not really the one to advise on the math as I’m still learning and not exactly experienced enough by half. I just know that you have to take all these facts into consideration because I’ve been making mistakes.

It’s the maths that are doing my head in because most of the good videos are from Americans and I’m from UK. It means I keep getting confused by inches per tooth, Surface Feet per Minute etc. I just need to sit down with a dummies guide I think lol.

 

New 2.2KW air cooled spindle/VFD arrived from e-bay, bracket 3d printed using 3d hubs (thingeverse design), cable from ZAPP Autimation Arrived today, wish me luck over the weekend

 

Depth of cut 3mm, depth per pass 1mm, roughing stepover 1.5mm. Chipload 0.1mm feed 1000mm/min

 

As a beginner that sounds okay... except you mean width of cut is 3mm I’m guessing lol.

Check the current on the X and Y axis drivers... bump them up a bit.

Also, and this is something that got me... check the grub screws are tight as they are easy to strip. I ended up getting new pulleys with larger grub screws and incidentally found that the Ooznest ones were the wrong profile (ie were not actually for GT3).


..............(Replacement Pulley - - - - - - - - - - - - - - - - Oozenest Pulley)

If you got yours from Ooznest you may want to check you have the right ones too.

 

I am waiting for the pullies of the new motors and will see if changing all motors and connections will make a difference

 

Are your pulleys the wrong ones too?

 

I’ve always considered a second bracket too!

 

Acrylic isn’t that hard. You should be cutting a max depth of about 1.5mm per pass. If you reduce the depth per pass you should be able to increase the feed rate and shouldn’t get too much deflection.

You might want to check the angle the bit starts the cut at. I know Estlcam has a setting for this, not sure about other programs. If your bit isn’t designed for plunging in you can end up with deflection and missed steps.

 

No but i am changing the motors to new ones that have a smaller shaft, so getting them new pulleys and coupler for the Z axis

when I started with 1.5mm depth I ended up with this....for a circle. That was a climb cut, I am then using conventional for the aforementioned cuts

 

You need a very rigid machine to do climb cuts. That’s one thing about the ox there is a bit of flex in the gantry and z axis of you put it under a bit of load. I considered bolting the gantry together mid section but this would mean i’d have to dismantle it or drill right the way through and that would be ugly.

Ooznest have a Black Friday sale on. I’m considering getting another mount for the router.

 

I got your point may be that is solely rigidity issue, but what about wrong dimensions of the conventional cut. I will try other bits and report back

 

As I said. Your ramping setting could be too sharp. So you are going to in too deep and sharp when you start cutting which could make it lose steps. Better to go in at a lower angle. It’s only acrylic though so that might make absolutely no difference.

Have you tried mounting a pen to the z axis and doing the shapeoko test pattern?

Make sure everything is absolutely square make sure your wheels aren’t binding by loosening off the eccentric spacers. Make sure your belts are tight but not too tight, pulleys are locked on to flats etc.

 

Marcus1

I would really appreciate the settings you mentioned for the MACH3/BOB and Spindle setup

I have it mounted and correctly wired up, and tried to run it last night (no luck). I did notice that the relay light on the BOB is not lit up (it was before)

Thanks in advance.

 

I wouldn’t even bother trying to do all the maths, it’s just one more thing to worry about.

Buy G wizard for a year ( you probably won’t need it after that ) and use CNC Router Tooling Speed and Feeds Calculator - Information

Most recomendations for depth of cut are for half the diameter. That’s fine if you have a really rigid machine. If you try going in that deep at a fast feed speed you will probably find your machine will flex especially on the lead in. Depending on the hardness of material you may get lost steps.

It’s just one less thing to worry about. Then you can focus on learning to use it and get to know your machine.

For instance. If I (as just mentioned ) try a depth of half the diameter of the bit, for most materials the cut is going to be ROUGH! If I made the decision to back off on the depth to say a quarter of the diameter and run at a faster feed rate but put more wear on the tip i’ll get a great quality cut first time with no roughing and the machining time will be the same as if I did it at half the depth.

You can also then not worry about easily killing any bits because you are going in shallow and not flexing the tool.

I’d always go fast and shallow over deep and slow! Fnar fnar.

 

@NeoMorph i believe I have the same Ooznest pulley. Can you explain the difference. Would it be worth my while to change out?

Thanks!

 

The Ooznest pulley is angular, more like a V than a U. As the belt teeth are U shaped it means you have to overtighten the belt to force the teeth into the pulley gears. This adds friction and you can see rubber being rubbed off into the bottom of the gears.

 

Forgot to mention... m4 grub screws in mine... 2 in each hole. First grub screw locks the pulley to the shaft and the 2nd grub locks the first in place. Works even better than M3 bolts.

 

Thanks for the tips @NeoMorph, most appreciated.

Robert

 

You’re welcome.

While I’m not an experienced CNC wizard I actually AM an experienced modder and I tend to look for reasons when the machine just doesn’t sound right... and I’m still trying to find the reason why the dual axis sounds crusty as hell on Ooznest machines because I would love to help those guys after being so good to deal with.

In fact, when I contacted Ryan Lock about it he sent me an email back about the pulley problem....

Most directors would woffle on about it being an alternative or more efficient one... but Ryan just admits they missed it as it comes from suppliers (in sealed bags no less) so it looks like they were sent the wrong pulleys.

I prefer the thicker pulleys because they are better in numerous ways.

• Right profile.
• Narrower channel to stop wandering of the belt.
• Stronger construction.
• Ability to use larger and multiple grub screws. (I think the original grub screws are m2 or m3... I replaced mine with m4 in the dual configuration.
• Better machining - the new ones are from Powge and look great. Hardly any machining marks while the Openbuilds ones while ok if you use a matching belt are just not GT3 pulleys. Just run an Ooznest one through some modelling clay like Plasticine or even Blu-Tac and you will see the profile is chopped off little pyramids from the side while GT3 is a half moon.

I think the pulley supplier is the one at fault due to the pulleys being supplied in sealed bags. I hope Ryan gets it sorted because I bet this is the problem with Ooznest pulleys sometimes skipping teeth... and if the pulley supplier is sending out the same pulleys to other Ox and C-beam machine makers... well it would explain why we have to double belt.

 

@NeoMorph could I trouble you for a quick link for the exact pulley you are using when you get a chance. I can usually find most anything on the inter web, but I must be searching for the wrong thing here. I have found many GT3 pulleys and I can definitely see the difference in what I have but the thing I can't find is the pulley close to the width of my belt. seems my belt is only about 4.5mm wide, would stand to reason that I might need a pulley about 5mm wide. that's where I am running into difficulty. I see 15mm wide and 9m wide but no 5mm??

Also, just curious on thoughts of steps per mm and calibrating. After diving into this crazy rabbit hole I found this ridiculously long article that explains the different types of belts and pulleys. One of my issues early on was my calibration was off by quite a bit, don't recall exact numbers but let's just say I could not cut a 20mm circle and have it actually come out 20mm. Could having the wrong pulleys be part of this issue? Seems if the tooth to belt engagement is off then it would have some cumulative errors over a given length of travel. Not sure if this makes sense or not. I guess I will find out once I replace the pulleys and report back.

Thanks again!

Robert

 

Here you go... guy who sells them is great too.

GT3 PULLEYS - 6.35mm or 8mm Bore - 20 Teeth - 3mm Pitch - 3GT | eBay

Edit: Looks like he only has 2 left. Just msg him and ask when he will get more in and ask him to put 3 5mm shaft GT3 aside for you. He did for me.

 

I cut acrylic all the time (both 1/8" and 1/4") and here are some tips.

- Single Flute O 1/8" bit works the best
- I currently cut at 12K RPM, 1 - 1.1mm DoC, 400mm per minute (thinking about trying increasing this to 600-700)
- CAST acrylic (you can cut extruded with this but watch for melting)

I run a 1000mm x 1000mm double belted OX with a 800W Chinese water cooled spindle with Hy VFD.

If you have any questions just let me know.

--James

 

I did the same on my 1000mm x 1000mm machine.... works like a charm.

 

Hi friends, hope you are all doing fine.

I would like to ask for suggestions about my board settings and ooznest ox. My board is a chinese lv8727, and i work with for two years now without any problem (knock on wood). There are some settings that i am not sure what is the best to choose. First of all my motors are 2.8A. The board current settings are 2.4A and 3.0A. I worked with 2.4A settings but recently changed to 3.0A setting. Motors got a little hot but not a lot to worry. My microstep settings are 1/8. And the next setting is where i need your suggestions please. Its called delay type on the board and i could choose 25%, 50%, 75% and 100%. On the manual its called attenuation mode with three setting slow, mixed, fast. So far i worked with setting to 25%, but after some issues, i am thinking if it better to change this. Setting to 100% its pretty noisy and a lot of tremble to machine. Setting to 25% or 50% seems a lot better to my ears. Please i would like to know your suggestions about what its better.

Thank you in advance!

 

Hi all,

I've gradually talked myself into thinking that buying a hobbyist CNC router would be a good idea. I have experience in operating a laser cutter, but CNC is new to me.

I've got two main uses for the machine: I do a lot of letterpress printmaking, so a CNC router would be a great way of making large printing plates from digital files, and I'm also renovating an old house, so there could be a lot of value in milling furniture components.


From what I've read here and elsewhere, I'm pretty confident that the OX is the best balance between performance, size, price, and after sale support.

I do have a few questions for those who are far more knowledgeable than me about these things;

1) I like the idea of being able to use the router as a conventional router as well as part of the OX. Has anyone used the Dewalt D26200 as a hand held router? Any feedback? Are there any other models which come with a detachable plunge base which would also fit the OX mount?

2) Traditionally when carving letters for letterpress printing, a pantograph would have been used to do the majority of it, and then it would have been hand trimmed to take care of any interior corners. Am I right in thinking that if a V shaped bit was used, the g-code produced would be able to cut sharp interior angles by raising the z-axis?

3) Has anyone had any experience of cutting pieces which are longer than the bed of their machine by cutting, repositioning the piece and then cutting again? Or is that too ambitious for a machine of this type?

4) I've seen people mention software plugins for Inkscape. Is anyone able to recommend one for Illustrator?

5) Finally, does anyone know if Ooznest do January sales? I saw they did a black friday one, but I wasn't ready to commit then.


Thanks for your help!

 

The problem with using the router as a hand held AND part of the Ox is you would have to tram in the thing every time you moved it back to the CNC and it can be a bit fiddly if you need to shim it.

I’ve got an Ooznest Ox and I love it.

 

1. As mentioned you don’t want to take the router off. Just buy another one for £150.

2. Yep!

3. I haven’t experience. You may have to mod your machine to enable this. It is possible. You will need datum points half way along.

4. There isn’t anything for illustrator. Everyone has a different workflow. Illustrator isn’t suitable for CAD. Mine is (whilst I learn how to use Autodesk 360 CAM ) Autodesk 360 - Corel Draw - Estlecam- BCNC.

5. Give them a ring!

Merry Christmas!

 

My 1500x1500 OOZnest has been working great for the past 6 months. Today, a weird little gremlin popped up on my Universal Gcode Sender screen. When I open up the command window, I get many lines of non-stop, repeating question marks. I've tried rebooting the software, rebooting the computer, disconnecting and reconnecting the USB cable from the computer to the Xpro board, resetting the commands and re-entering all the settings as indicated in the OOZnest manual. I also dumped the UGS and reloaded it on my computer but I still get the repeating lines of question marks. They stop repeating as soon as I close the commands tab on UGS.

I opened up the machine controls tab and entered 10 mm x,y, and z movements and they seem to operate the gantry controls properly, but I'm hesitant to do any cutting with this gremlin lurking around in my machine. I've attached a screen capture. Any suggestions would be greatly appreciated.