how to force FlashForge Pro to heat both platform and extruder at the same time?

[Printerkiller]

I use FlashForge Pro and apparently I have a 7.7 firmware (At least by Makerware info) and every time I start a print - FlashForge preheats the platform and and only after that the extruder. How can I change this setting?

Thanks in advance

[soofle616]

I was just thinking the same thing. I always assumed it was a makerware thing but s3d does it as well.

I don't have a solution but a workaround to get prints going faster is to use the preheat option on the printer LCD. Once you get things turned on go into utilities-home axes. That will home everything which is the first thing every print does. Doing it manually gets everything where it needs to be because when the print starts it's going to turn off your heaters and things will start to cool off while you wait for the build plate to home. If it's already there the plate and carriage will move to their initial resting positions right away and things will stay hot. I run through all this WHILE I'm preparing my print on my computer and getting it onto my SD card. That way by the time I'm actually ready to print, so is the printer.

[jfkansas]

The extruder takes about a minute to heat up, where the build plate can take 5-10 minutes. The firmware is designed like this because of the limited power supply current. It takes more power to heat the build plate than it does to maintain the heat. When the build plate gets within a couple degrees of being up to temp the extruder heater circuit kicks on.

[tigerprinter]

The firmware is designed like this because of the limited power supply current.

I've printed files generated in ReplicatorG or Slic3r that heated the build plate and extruders simultaneously without changing my firmware. I think it might be software-dependent.

[jfkansas]

Probably a Gcode command that overrides the firmware. There isn't any reason to heat both at the same time. If you heat them both at the same time the extruder will sit there fully up to temp for 7 or more minutes. This isn't particularly good for the hot end since it is cooking the filament for a long period of time with no cool filament being brought in. Ideally you want the extruder to come up to temp and then immediately start printing.

[Mjolinor]

It is not sensible to do it any other way than build plate, extruder.

If you do choose to do it another way then you run the risk of burnt plastic or an empty extruder.

[Printerkiller]

Thanks for the response, didn't think about the extruder waiting angle

[soofle616]

I still see no reason to wait for the plate to come fully to temp before starting the extruder. Yes I understand that the extruder only takes a couple minutes to heat fully but that couple minutes could easily be saved by combining it with the plate heating. Instead of waiting for the build plate to reach 98-99% of the desired temp the extruder could come on earlier, reach full temp right about the same time and not have any potential issues from sitting and waiting.

As for burnt plastic or an empty extruder... Burnt plastic I can see causing a problem with jamming but so what if the extruder empties? The initial nozzle purge before each print should correct for that.

[Mjolinor]

If you have an initial nozzle purge it should but will not always. There is also another problem with heating the nozzle and not using it. If the stepper is not powered during the heat cycle and the carriage is moved then the nozzle stepper can rotate due to crosstalk or filament tension and unload itself. I have seen this happen on my Wanhao.

The solution is to set the bed temperature at (for example) 100 and not set the nozzle temperature at all, issue an M109 so it sits until the bed gets to 100 then issue the extruder temperature and a revised bed temperature then another M109. With experimentation you will be able to set the initial bed temperature such that the last few degrees take the same time as the extruder to heat up. This needs doing in your start.gcode file.

[DrUsual]

The Flashprint software that ships with the Dreamer actually has a setting for a build platform threshold before triggering the extruder heating -- I don't recall how adjustable it is since I've been using Simplify3D for the past few weeks, but I remember seeing it in there. I haven't looked for the same possibility in Simplify3D for the reasons mentioned above -- it only takes a minute for my extruders to heat after the platform reaches its heat, so it's never bothered me to wait a bit.