hello that machine frame is looking pretty good, Ill follow your work and most interested on the Hiwin rails for my build upgrade, one small advice from a been there done that fellow Co2 builder,, try to build the X Y stage as a separate unit from the frame, like a floating unit, it will make your life a breeze when time says it is time to align everything out, mostly and more critical on the size you are working on, best wishes on your endeavor!!!

 

What linear rails and blocks models are you using for this build?

 

still on the look on what to use, have you test your x y motion already? how you like it?

 

Thanks, are you using normal 2GT or something else, Belt width, im about to jump into rails soon bur afraid to buy the wrong stuff!!!

 

Hi CChico,
Great work ! Have you thought of a belt less system? Or is the cost of a ball-screw based system way too high?
Also:- How are you planning on metrics?
*Accuracy *Precision & Throughput
ThanX!!

 

>>I think but the score mark that the laser makes is much bigger than that so in the end, you wouldn't be gaining much as far as precision.
Hey CChico: Thanks for the reply. The Std. Dev (Sigma) would need to be added to the Laser score mark dia. So in the case of a belt system the (Sigma)^2 would
get larger as you progress through the workload (due to heat generated via friction).
Probably a non-issue, for cutting, however, maybe an issue for fine engraving.
BTW:- Do you have belts on all axes?
Also I presume you're planning to run Stepper's w/o encoders?
TIA
-SVeda

 

I purchased the open builds 1000mm 20/40 setup to start with, are you concerned about the sag/flex you will get on your axis as your head travels?

 

>>are you concerned about the sag/flex you will get on your axis as your head travels?
Hi Mike: Yes. However, there are at least '2' components to the above.
1. Static Component (at the very beginning of a workflow, for ex):- where the sag/flex will add (or subtract) to the variance in positioning.
2. Dynamic Component: (Where the Sag/Flex will include a Temporal variable to the process).

Again ...these are non-issues, if cutting to a tolerance of say +/-1mm (in this case)
However, if you changed the Laser (and hence the spot dia) and have a spot size to be 1/10th of +/-1mm, then we have an issue.
You would probably change the laser and the optics (and hence it's spot size) for fine engraving.

So Basically:- I was asking if ball screws could be designed in (to greatly reduce environmental variances, like temp & humidity).
Maybe an "Over-design" for coarse cutting, but would make the machine more deterministic and multipurpose.
Regards,

 

CChico:- How RU? I would recommend leveling feet. You could still use the rollers. The leveling feet will give you the ability to level out the garage floor, for ex.
Best,

 

"My 80w Chinese laser came with an extremely loud exhaust, air assist, and water pump, all 110v. My goal for this build is to replace all those peripherals with DC components so that I can eliminate all those loud components with much quieter ones and so that I can eliminate all those plugs and control everything directly from the laser (that's the purpose of all the buttons in the front of the machine.)"

Hi CChico,
Howdy? Regarding your recent post (in quotes above). If you moved the Laser Cooling function to the DC side, you're introducing a Single Point of Failure.
So basically, when the DC power supply fails (or has anomalies), you're Laser has ZERO cooling! You'll be shortening the Laser tube lifetime.
Also:- On the performance side, your cooling anomalies will influence the Laser beam variances. These anomalies maybe subtle and not noticeable w/o cooling metrics (via data logging) and measurement of Laser parameters (in real time, over a specific time period).
Regards,

P.S. Have you planned for a Cooling Malfunction Interlock (which would shut power off to the Laser)?,

 

Hey CChico:- 'Morning! My intention is to be a Skeptical Design Reviewer, as I do in my professional life. I hope I don't piss you off :>)
I learn't Precision Machining from a "Guru" at LLNL, hat's off to Jim Bryan!
So basically we would start the design '2 ways:- a) Top Down approach (most folks do this) & b) Bottom up Approach
When we have a Technical Risk and or a Business Risk, we need a "Bottom up approach" to retire the risk(s) in question. Let's cast aside the Business side, here.
So:-
The known Technical Risks (not a complete list by any means), for example:-
1. Tool Positioning Precision (Accuracy maybe derived thereafter by calibration). To keep it simple let's say: This is @ room temp (25 Deg C)
2. Laser Beam Parameters, over time & more importantly over the work area.
3. Reliability: Let's look at this Top-Down, as we would need a HALT test in a chamber for a meaningful reliability test.
a) Keep the Laser tube H.V. Controller & Cooling accessories independent of the motion system. Reduces dependencies & eliminates unwanted performance
related variables.

To test for '1' we would need encoder info from the steppers and plot it over commanded position info. Don't know if you're running open loop on the steppers.
To test for '2' you'd need a beam profiler (with a suitable attenuator, since the laser is 80W optical pwr). And profile the beam to extract the beam parameters over time and the extremities of the work area. There are plenty of USB/Ethernet based beam profilers.

Depending on the results of test(s) '1' & '2' we would need to tweak the machine.
For example:- Maybe at certain extremities of the work area the beam loses 10% or more of it's power. We need to find out if the motion system/the laser beam coupling optics are contributing to this variance.
Regards,

 

"When I push a button to turn the water pump on, it also turns on my water temperature display, and it also turns a light on behind a visual water flow indicator. I’m also looking into getting a water flow sensor which are relatively cheap"

CChico:- Are you implying that the water pump needs to be turned on manually? The Laser operates at it's best spec (as specified in the data sheet), with a 21 Deg to 25 Deg C, so probably best to turn on the Laser cooling accessories independently of Laser power. If the Laser Cooling is powered on with DC, loss of DC pwr is detrimental to Laser performance and lifetime. Even with an interlock to trigger the event.
Best to use a Chiller to control the temp to the Laser. And interlock the Laser AC i/p pwr to the Chiller alarm O/P. An added advantage is that when you switch the Laser pwr off. The chiller stays on.

Also:- The more the number of sensors, the lower the reliability (measured as MTBF & Uptime, for example). The flow sensor is great for secondary confirmation of flow, not for a Primary Interlock, because when this sensor malfunctions (SW can't figure this out easily).
Regards,

 

Quote:- "I can jog the motors using lightburn right now and get the laser head to move, but when I try to start a job depending on where in the bed it is located, it grinds and loses a lot of steps but that’s another issue for another day."

Hey CChico,
How's it going? Cool pics! I happened to notice the above ( in quotes). This usually occurs because of excitation of natural frequencies (Mech & Electrical). The best way to avoid this is to use a PROFILE to drive the Stepper. Pay around with the controller SW and reduce the slope of the Trapezoidal profile(s), if provided use a SW notch filter, as well. Since it's very position dependent, you could also try Mechanical Damping. Of course, all this assumes that the belts have the identical tension all over the work area. Hope this helps.......
Regards,

 

Quote:- "I also did find out that the original grinding noises was just me being dumb and not checking all my settings. I told the software how big the print area was but under the controller settings I had 200x300 so when I the head would try to move past the given parameters it would just go heywire."

That's funny! A good problem to have, as long as it's trivial to solve!
Keep us posted. TIA.
Regards,

 

Hey CChico,
How RU? How's the build coming along?
Regards,

 

Hey CChico,
It's looking good! Feels like it wants you to dance along, while it's cutting!
BTW:- Are going to add the rotary attachment as well?
Regards,