Showing posts with label Aliexpress. Show all posts
Showing posts with label Aliexpress. Show all posts

Friday, 14 August 2015

Scara 3d printer cost calculations for V1

Approximate cost calculation for V1:
  • 51$ — 5 Nema17 (you need only 4, so you get 1 for spare parts)
  • 32$ — Ramps 1.4+5 Dvr8825+LCD (you need 4 drv8825, so you get 1 for spare parts)
  • 7$ — E3DV5 (china made) with 1m PTFE tube (0.5m for spare parts)
  • 2$ — extruder gear
  • 6$ — gt2 pulleys and gt2 belt
  • 5$ — 6mm smooth rods (2x20cm)
  • 4$ - 4 LM6UU linear bearings
  • ~10$ — ball bearings+bolts+screws+other stuff
  • 10$ - external power supply 8.5A 12V



Total: 127$ (with power supply, but without ABS filament — approx 200g)
NOTE: All prices from my aliexpress orders, free shipping to my country, no taxes (in my country taxes begins only from 200+$).

NOTE2: V2 seems to be in the same price level, but not cheaper.

Ways to save costs:
  • ~8-10$ - get rid of of LCD module 
  • ~5-7$ - Replace one Nema17(for gearbox) to small 2.5$(28BYJ-48 12V) stepper + printed high ratio spur gears.
Not a lot.

More global idea:
Replace 2x10$  Nema17 steppers to cheap DC MOTOR + Hall Sensor + L293N + gearbox. The main problem is a backlash free gearbox. I think gearbox should have approx 1:100 gear ratio.

Backlash free gearbox ideas.
  1. Looks like it is possible to combine 2 stage of 1:10 belt driven gears. Belt driven gear theoretically backlash free. 1:10 belt driven gear is a 16 teeth gt2 pulley and 160 teeth pulley (~101mm diameter), or use more stages with less teeth pulleys (seems like better due to the less belts length).
  2. Planetary gears - at least 2 stages required - i tried to print - seems like printed does not work well.
  3. Hypocycloid Gear - looks better but seems like it does not work due to printing precision, plus vibration may affect print results.
  4. Harmonic drive - not tested
  5. Classic gears - seems like not backlash free, there are a few ways to decrease backlash, but i not sure.
NOTE: It is just an idea

Saturday, 18 July 2015

Scara hot end

Current PTFE based hot end is bad.
I have super idea how to use cheap and common E3D V5 (long).
Idea in short: One end effector arm is extended a little bit and hot end will be attached to this place (actually any extruder), firmware math required a few extra calculations.
Wait for images in near future.

E3D V5 like hot end on aliexpress

Sunday, 31 May 2015

Aliexpress stuff

Cheapest NEMA17 steppers

http://www.aliexpress.com/item/free-shipping5-PCS-17HS4401-lot-4-lead-Nema-17-Stepper-Motor-42-motor-42BYGH-1-7A/1511814261.html

This is the start of my 3-rd 3d printer based on 5-bar mechanics.