Is 40mm cube too big for my machine?

I have a RepStrap with gen 2 electronics running the RepRap host software. I'm trying to print out a 40mm cube as a test for my machine. For some odd reason my axis are going way too far off my machine. It seems like the cube won't fit on my build area. But, my build area is bigger than the 40x40x40mm cube. I tried moving the cube around the build area in the software but it still goes too far. Also, with the threaded rod drive system; how long does it take to print out this cube?

I'm sorry I can't explain this in any more detail. I'm very confused myself.

Thanks,
Drummerboyx

Sounds like your firmware settings are way off.

parameters.h of the firmware should have something like this:
#define X_STEPS_PER_MM 7.99735
#define X_STEPS_PER_INCH (X_STEPS_PER_MM*INCHES_TO_MM)
#define X_MOTOR_STEPS 400
#define INVERT_X_DIR 1
[... also for Y & Z]

Important information you need:
- Steps of you stepper motors (200 for a 1,8° one), multiply by 2 if you use half-stepping
- Steps per mm: On a threaded rod you can calculate by MOTOR_STEPS/THREAD_PITCH. So, on a metric M8x1,25 rod, this is 320 steps/mm on half-step 1,8° motor.

After changing this, test the movement of each axis separately and ensure they go the way you said them to go.

---

-------------
FiveD Firmware fork (supports Arduino Mega): [github.com]
reprapsource.com

Thanks! I'm going to try it out later today but I'm sure that's what my problem is. Also, how long would it ussually take to build somthing like this on my machine?

Thanks,
Drummerboyx

Threaded rod machines struggle to go much faster than 4mm/s.

If you extrude 0.5mm filament that is pi/4 mm^3/s of material. A 40mm cube is 64000 mm^3 so it would take 22.6 hours to make it with 100% fill. Typically 25% fill is sufficient so that would be about 6 hours.

You could also go for a lower resolution, for example if you use 1mm filament it will be four times quicker.

---

[www.hydraraptor.blogspot.com]

I'm confused...what do you mean by a 100% fill and a 25% fill? So if I did go with a 25% fill would the build take only 6 hours? Also, what is a filament? Sorry I'm asking all these questions but I could never figure out what they meant.

Thanks,
Elijah

RepRap machines draw an outline of each layer and then fill it in with a zig-zag to make a solid object. The zig-zag fills in 100% of the slice on the outer layers but can be much sparser on inner layers. That saves plastic, reduces warping and speeds up the build. The objects are not as strong but plastic 40mm thick is incredibly strong anyway, even when only filled 25%. I.e. with each of the inner layers having only 25% of the area filled. See the second picture in this post: [hydraraptor.blogspot.com]

Filament is just the name for the thin stream of plastic that comes out of the nozzle, roughly the size of the hole through it. It literally means a fine thread or wire.

---

[www.hydraraptor.blogspot.com]

How can I change the fill in the RepRap host software?