Print_Radius problem

[chbeckdb9]

Alright, so I'm so close to being able to print. I am at the point of running script 4. The machine grabs a piece of paper really nicely with scripts 1-3. However I keep adjusting script 4 and each time it still pins down the paper. I am at around 194.05mm and started at 197.25. It really has not helped any dropping the amount. Each time I edit, I disconnect, then enter arduino, then edit the " print_radius" then save, then reconnect to printer and run scripts 1-3 again, then try script 4 again.

Also how do I invert the extruder stepper motor direction using the arduino software, I can't seem to find the proper line of code?
Thanks!

[JohnStack]

There are a few posts about this - but in general, you might need significantly lower or higher values than changing 4 - 5 at a time.

Also, fair warning - sometimes the settings won't burn into the eeprom as you would expect. You might first try powering off or doing a reset / reburn...

(You're not the guy printing the DB9, are you? If so, I'd like hip tips!!!)

[m4r1n5]

I did figure out that through Arduino's "Configuration.h" you need to 1) set EEPROM to 0 2)load 3)set the Printer radius 4) load 5) REset the EEPROM back to 1 6) Load. THEN start your calibration from the beginning, through Repetier. From MY short experience with this, MY PRINTER (not sure if ALL printers have the same outcome) hotend extruder moves DOWN .3mm for every 1mm I enlarge the "#define PRINTER_RADIUS".

Hopefully this will help some.

[chbeckdb9]

Hey,
Thanks for all the replies. I went ahead and tested the extruder and and no matter how I set the " ext_inverse", when I click the " extrude" on the manual control panel it sends the filament in the wrong direction. I was hoping I could simply do the " true/false" for the inverse config.h and it would reverse it, but no luck. What am I missing? Also I could switch two of the wires going to the extruder motor, however I am not sure which 2 of the 4 need to be switched.
With the arduino, as long as the machine is disconnected, and I make changes to the code, then save it, then reconnect it should work right ?
Thanks again!
btw.. No I'm not the guy trying to print the full size Aston Martin DB4. Here is a link though http://www.wired.com/autopia/2013/07/3d ... on-martin/ Pretty cool stuff!

[cpunches]

Try switching pins 1 and 2, that should reverse the direction.

[Cleveralias]

Hey,
Thanks for all the replies. I went ahead and tested the extruder and and no matter how I set the " ext_inverse", when I click the " extrude" on the manual control panel it sends the filament in the wrong direction. I was hoping I could simply do the " true/false" for the inverse config.h and it would reverse it, but no luck. What am I missing? Also I could switch two of the wires going to the extruder motor, however I am not sure which 2 of the 4 need to be switched.
With the arduino, as long as the machine is disconnected, and I make changes to the code, then save it, then reconnect it should work right ?
Thanks again!
btw.. No I'm not the guy trying to print the full size Aston Martin DB4. Here is a link though http://www.wired.com/autopia/2013/07/3d ... on-martin/ Pretty cool stuff!

Regarding arduino, your steps are correct but after saving you then need to use the 'upload' function to get the firmware on the board. Maybe that was understood but thought I'd mention just in case.

In the firmware, although I haven't had to use it, it looks like EXT0_INVERSE should do the trick. Make sure you're adjusting EXT0 and not EXT1 in the firmware (even though it's referred to as extruder 1 in EEPROM it's extruder 0 in firmware).

Also, you should make the towers equal with scripts 1-3 then set Z height based on the center - script 4. Then you can go back to the firmware and adjust delta radius (this is the parameter normally adjusted for the concave/convex correction rather than printer radius, btw). So you know what you're looking for, after you've made a change to delta radius, the center height won't change; only the towers will (scripts 1-3).

[chbeckdb9]

Thanks!
I still can't get the " extrude" to move the filament the correct way regardless of if it is set to true or false. I've double checked all my steps and I am uploading etc etc correctly I believe. Not sure what is going on.

It is showing a code error. I attached a pic. I have not edited this area of code at all, but it shows this error message when I upload it.

[Cleveralias]

Do you have the correct board (mega 2560) selected under tools --> boards? Confirm that first, then you can use the 'verify' button to check for errors before attempting to upload. If then you still show the error, I would grab a fresh copy of the firmware and start over as I don't know where that error would have originated.

[jonyzdude]

ok. My x , y and z are dead on. when I run script 4 the head stops 3/4 from the hot plate. this would indicate that I have a convexity issue correct? so when I go into change the printer_radius number it does nothing when I run script 4. It returns to the same spot every time whether i change the number up or down.

[geneb]

Read the instructions. I can guarantee you that they don't say the only thing you do after changing PRINTER_RADIUS is just run script #4 again.

g.

[edward]

Maybe I should write a bot to do translations for you, gene

char* translate_geneb() --> "You have to re-run ALL of the scripts, starting with 1,2,3, after making any change to PRINTER_RADIUS or other geometry related firmware parameters."

[geneb]

Page 164:

"Once you've uploaded the new firmware, you'll have to re-calibrate the base of each tower as
you did in the previous steps using Scripts 1 through 4. It may take a number of iterations to get the
center nozzle height nailed down, but it IS worth the hassle."

That's about as vague as a brick to the face. Hey! There's an idea....

g.

[lordbinky]

I think the issue is that people change their print_radius it would be natural to expect the Z height of the center to move after they just calibrated the three tower points, which is the opposite of what print_radius is changing. So including something along the lines of 'Note: Printer radius is changing the Z height at the tower base's relative to the center, NOT changing the center based on the perimiter.' should at least get people closer to thinking in the right perspective.

[edward]

blinky, I do agree with your premise of confusion; this example is one of the many peculiarities of the delta that makes it so non-intuitive. But, I'm not sure additional reading material is actually going to help.

[lordbinky]

It's frustrating when your mental model isn't matching reality, and although if you explicitly follow the instructions you'll get there eventually, it doesn't make it less frustrating if they never get why it worked out and they are still picturing things wrong. It's also the first time any geometry issues in the build make theirself obvious misplacing the cause of their frustration and make this first print_radius calibration experience extra gruesome and confusing. While if they followed the instructions just right they shouldn't have those issues, it just adds to the frustration for the first time going through the process.

Stressing the importance/criticality of something in literature is necessary, but typically fails because of human nature (typically people overestimate their abilities and probabilities for success). So at least an upfront 'this changes this' explanation would be a proactive response to a common problem and a different approach that may be more effective for a different set of personalities than a red bold italic 'really reall important, i mean it' is in an earlier step.

[edward]

Well put. I suppose one thing that could help is if those of us with the "this changes that" experience aid Gene with the manual...if he wants it.

[geneb]

I'd be happy to add an explanation of the "why" in an appendix, with a pointer to it from the calibration section. I just don't want to be the one to write it.

g.

[jonyzdude]

so then what script do i run after i change the EEPROM to "0" and lower/raise the printer_radius number. Since I ran script 4 last and the z height is maxed out, it wont allow me to go any farther down unless I change the z height.

[edward]

Then you seem to know what to do. If you don't have enough length in your end stop screws to take up the height difference (that is, can you screw OUT the screws the 0.75" that you say the hotend is above the build surface in the center?), change the z-height to something that allows you to reach the surface. Then, start at step 1 and iterate steps 1-4, adjusting the needed parameters until you get a good test at all three towers and the center, i.e., a passing/good/positive 4-point calibration.

[lordbinky]

What I did before I started using a dial indicator and I wasn't close to the proper print radius is leave the Z-height short and use something to compare heights. For example: get your center Z height around the width of a ruler. Then you try to get the points at the tower base the same height to each other (ignore the center for a minute). Then once those are equal, you can use the ruler width to compare the height of one base to the center (the points at the tower bases are equal at this point, right?). Then you make your concave, convex adjustment in firmware, re-upload, and get your tower base points equal again, compare and adjust. When it finally gets close, set your Z height big, and just carefully move the head down to where you want it (paper test), and use that Z-height. Then I would do the fine tuning paper test adjustments. The benefit of doing it this way is you are less likely to ram the bed really hard. I might do things the difficult way though.