Shenhui Autofocus, Frame and Origin

[Shane Sura]

I have searched and searched and it seems no one has had the same issue. I also have an email into Shenhui but with the time difference I figured I would ask here. I am having two issues that I want to clear up before proceeding to my first job.

-- The first is focus and the second is the frame setting. As for the focus when I try to use the autofocus it raises the table but never stops. Twice it has crashed into the work piece and when you reengage the machine after hitting the E-Stop if returns the head to home doing further damage. I have realigned the head perpendicular to the table and am trying to figure out why the autofocus is not working. I am assuming that the focus mechanism is this:

2013-01-05 18.54.00.jpg

So what I tried was hitting the autofocus and pushing up on the mechanism. While the mechanism moved it did not stop the Z. So I am at a loss to what may be happening. In addition, I was not provided any focus sticks so I do not know the distance to focus. Can someone tell me so I can at least do it manually? For now I am using the bottom of the mechanism but have zero clue if that's right or not.

--The second problem I have, that I think will cause problems in running jobs, is how large the machine thinks the frame is. When I hit the frame button it goes to home (top left) and then jogs almost to the bottom (around 11 inches) then over around 4 inches then back up. This is telling me the machine thinks the size of the bed is only 11x4. I have checked the machine settings in the software, by using the password rd8888 and X is set to 500 mm and Y is set to 300 mm. I cannot find any other setting that would indicate a smaller breadth.

--Finally, and related to the previous, while I was playing around with the frame setting I tried setting the origin. At first it would not work because I tried setting it outside of the smaller 11x4 rectangle that the machine thinks is the frame. Then I tried setting it inside that area and it did take. Now the issue I have is I cannot clear it. I have tried setting it at actual 0,0 but it still returns to the new origin. I also looked in software but do not see any indicator where to change.

Thank you in advance for the help. I did really try searching and after about 2 hours of reading posts I gave up and figured I would ask. Thanks!

[Rich Harman]

It appears that the autofocus plunger is mounted too high, the nozzle will contact before the plunger engages. If that is the case you will need to lower the plunger and then have the correct value entered in the settings for the auto focus.

Easiest way to find focus is to lower the table and lay a long (~12") piece of material on the table with one end propped up. Manually fire the laser while jogging the head across the piece. The idea is that you will engrave a line on the piece so that each end is out of focus but somewhere in between is correct. Without moving the piece closely examine the line to find where it is narrowest - that will be where it was in focus. Now move the head directly over the in focus part and use the distance between the nozzle and the line to fabricate a focus stick, even a piece of cardboard will work.

Not sure about your second and third problem. It sounds like your controller is different from mine. If possible, a video would help a lot.

[Jimmy Phillips]

I have a Shenhui SH-G690 with the same autofocus setup and I have experienced what you have described in the past.

This is what worked for me and what I suggest:

Take your table all the way down (-Z) to the bottom. This will give you plenty of room to test.

Then make sure that the wire coming out of the top of the sensor is not bent. It must be vertical for at least .5 inch out of the top of the sensor. You can also move the plunger location, so move it to the side or something so the wire does not have too much deflection. The reason is when the plunger is depressed an LED is engaged which is picked up by a photodiode. This is tied to your controller board as a Z limit stop. Now I could be wrong so this is just me guessing since I have not actually taken it apart, but I have seen the red LED firing in mine when I depress the plunger.

So the test is to hit your autofocus and while the table is rising, keep the plunger depressed and fiddle with the wire coming out of the top of the plunger until the table stops. If the table does not stop then most likely the LED is not coming on, the photo diode is bad, there is a disconnect in the wire somewhere, bad connection at controller board for Z limit in, or worst case the board is bad.

Of course you could say screw the autofocus and use a focus stick based on the focus lens you are using.

I don't use the frame setting on the panel so I cant help there. I setup the table dimensions in Corel and use that.

Good luck,

Jimmy

[George M. Perzel]

Hi Shane;
I don't have autofocus on my Shenhui so can't help you there-see file below for focus sticks for various lenses, which you can cut out of 1/8" plexi.
The Frame setting refers to the outside dimensions of the project you are lasering-not the size of the table. From my viewpoint, its only use is to determine whether the project will fit on the laser table based on where the home position is.Table settings are set in the software-vendor settings and page size.

FocusSticks1.cdr

[Shane Sura]

Thanks guys for all the help. A couple of comments:

Rich - The autofocus was slightly lower but it was close. As to your thought, I have read about that on the forum but I don't quite get the concept. I lay it at an angle and look for the crispest point in the line. I get that. But how close should I position the nozzle to the highest point on the stick?

Jimmy - I did try that this morning thanks. Still no joy I played with the wires and plunger but it did not activate. I did check software and Z is set to Enable Limit Trigger. I also found focus depth and it was set to 0. I tried a number of higher numbers no luck. I did verify that the light inside the sensor is firing

George - Thanks for the file! Completely newb question though. How do I know the size of my focus? I thought it might be the focus mirror size but thats around .7 inch or 18 mm. Then I thought it might be from the convex mirror to the end of the cone but thats 1.3 inch. Maybe it means its a 1.5 because its 1.3 then + the focus stick? Its about all my brain can deduce.

All - As to the origin / frame issue. George was right frame indicates the job. However, with no job loaded it still jobs a mini frame. I took two videos to show. The first you will see me job to 0,0 in the top left and hit frame. I get an error indicating frame slop hit enter anyway and it goes to this origin point and then jogs a mini frame. The second video is one in which I loaded a rectangle job that was 4 inches by 4.5 inches. In this one I hit frame and it starts again from the fictitious origin point and then jogs the 4 x 4.5. This tells me a couple of things. First, all jobs will try and start from this origin point. I have to be able to find a way to clear it. Secondly, if the job is bigger then the mini frame shown in the first video it will always indicate frame slop and will most likely not fire. I verified this buy building a larger rectangle outside that original 11x5 mini frame but intersecting the first rectangle. When I tell it to track frame I get the frame slop error unlike when I just had the smaller rectangle. So the machine is really thinking the size of the bed is much smaller than it is. Any way here are the videos.

First:

[Shane Sura]

Second:

[Shane Sura]

One more update. I checked the wiring and everything leads back to the mainboard and the three wires are plugged into +5V, Limit Z- and GND. Checking voltage the +5 does give 5. The Limit Z- is 3 volts until I push on the focus sensor then it goes to zero. So that should indicate the sensor is working there is just something in software not set right.

[Rich Harman]

Rich - The autofocus was slightly lower but it was close. As to your thought, I have read about that on the forum but I don't quite get the concept. I lay it at an angle and look for the crispest point in the line. I get that. But how close should I position the nozzle to the highest point on the stick?

Depends on the focal length of lens you are using. You probably have a 50mm lens.

I use a 63.5mm lens and have about 30mm of space between the bottom of the nozzle and the work piece. If I switch to a 50mm lens I have about 17mm. So arrange the long piece so that one end is well beyond the max focal length and the other end is fairly close to the nozzle - just make sure it doesn't make contact.

[Shane Sura]

Depends on the focal length of lens you are using. You probably have a 50mm lens.

I use a 63.5mm lens and have about 30mm of space between the bottom of the nozzle and the work piece. If I switch to a 50mm lens I have about 17mm. So arrange the long piece so that one end is well beyond the max focal length and the other end is fairly close to the nozzle - just make sure it doesn't make contact.

Thanks Rich....I know a stupid question but how can I tell what my focal length is?

[Rodne Gold]

I think Shenui normally send their stock machines out with a 37.5mm lens ..or 40mm.. I could be wrong tho in your case.
Contact Shenui via Skype , Yarde feng (yarde_feng)or Blanca yan (blanca610616) and ask for a config file for your laser or let yarde go into your puter remotely and set the machine up. Their online tech support is good.

[Shane Sura]

I think Shenui normally send their stock machines out with a 37.5mm lens ..or 40mm.. I could be wrong tho in your case.
Contact Shenui via Skype , Yarde feng (yarde_feng)or Blanca yan (blanca610616) and ask for a config file for your laser or let yarde go into your puter remotely and set the machine up. Their online tech support is good.

Thanks Rodne...what are their hours of tech support coverage do you know?

[Rodne Gold]

They work hard there , approx 8 am or so to 6pm , they normally take a long lunch..not sure how that translates to your time zone. Blanca can call Yarde to help you.

[Khalid Nazim]

What have you set in the Config > System> General Settings tab? See the image below. You need to ensure that the absolute coordinate option is unchecked. Second, Laser Head options indicate your selection of where the head is relative to the graphic file.

Config img.jpg

[Shane Sura]

Mine is set similar except I have the Axis X mirror unchecked as the manual said to do this for top left:

Capture.PNG

[Khalid Nazim]

I am on EST as well and I have worked with their tech support from 6PM EST onwards. I get support from Joy Yang (skype ID/name wm03511) and he is fantastic.

I also opted to get the autofocus arrangement which was a good thing for a while but a couple of things forced me ditch it and use just the focus sticks. First, the autofocus plunger holder is fixed on the nozzle. So whenever I had to clean the lens, I had to take the plunger out (I had to make line on the plunger to ensure that I put it back on the right height) as the nozzle would not open. Second, the z-axis focus calculation for the autofocus arrangement to work is for a particular lens. Whenever you change the lens you have to change this setting in the vendor file.

So after a month of autofocus madness and an accident that misaligned my head and ......, I moved to using the focus sticks and I am happy camper

Regards
Khalid