FLA-100 CNC Router

Filled under: Fabrication

Date posted: January 17, 2010

 

Overview:

Assembling a FLA-100 CNC router table.

The majority of the CNC router table components come from the company Fine Line Automation in a kit named FLA-100. The kit includes the 8020 aluminum extrusion, steel rails, threaded rods, bearing blocks, carriage blocks, motor couplers, and fasteners. Not included is a router, a router mount, stepper motors, motor drivers, PC, software, dust collection, a table top, a clamping system, etc.

The machinable area is currently configured to be 23.5″ x 34″ with a Z travel of 3″.

 

The Pictures:

My intention was to make an elaborate picture journal detailing every step of the assembly process, but I was behind schedule and my temporary shop location was an unheated back porch where the temperature was an average of 20F degrees. It was fortunate I was able just to complete the machine without frostbite. =P

 

Here are the fasteners, bearing blocks, carriage blocks, z-plate, router mount, motor mounts, lead nuts, and couplers.

The 8020 aluminum beams. They are surprisingly heavy.

As you can see these aren’t soda cans. The beam are thick and have extremely low deflection of only a few thousandths of an inch over several feet at heavy loads.

The threaded rods are 1/2-10 5 Start Acme Leadscrews. Some of the cold-rolled steel rails have dings on the edges but it turns out that those dings do not effect the machine’s cutting accuracy. Also, the rails are slightly bowed, this at first was a great concern, but after mounting the rails to the 8020 they straightened right out.

The majority of the electronics.

Ok, a good start. The base frame is setup and the machine is beginning to take form. Since there was no instructions and only a CAD drawing, I missed a few things on the frame and had to take it apart to add the required t-slot nuts.

The Z axis assembled and ready be fit onto the gantry.

The X axis with the attached Z axis.

The gantry is now attached to the base frame. It took a little bit of clamping to get the carriage blocks to be tight against the rails. The racking is mostly eliminated.

The motors connect to the motor driver by DB9 connectors. So after a few minutes of soldering, the motors are ready to be attached to the machine.

Everything is mostly setup and ready for parameter entry and general testing.

Ok, a little bit better being off the cold floor.

snowed_in

Meanwhile, the outside of my temporary shop remains cold and snowy. Over 12 inches of snow in two days!

The machine controller is MACH3. This program is very popular among hobbyists and professions alike. The PC  is running a clean install of Window XP and so far it has been perfectly stable.

This is a picture of my first cut setup. I was snowed in so I could not make it to the box store to get MDF for the router’s table top and the itch to make something, anything, was too great to be ignored. I did the only thing I could do safely, bolt down a 2×4 and cut that, so I did. Engraved are four zodiac symbols.

Aries, Taurus, Gemini, and Cancer cut using a 1/4″ V-bit. Having no experience using a CNC, or even a hand held router, I was happy with the result and the fact it worked the first time.

The Gecko g540 stepper motor driver with everything connected. (except the limit/home switches)

The wiring is straight to the point. I also installed a cooling fan which blows on the back of the g540, this likely not even needed. The spindle is activated by a simple car relay switch.

 

 

Research and Design to Assembly:

After several months of casual research and a few weeks of intense digging down, I found a machine which was a nice balance of size, rigidity, and cost. Three months latter I had all the parts in hand from about a dozen sources. From there, it took about a week to go from dozens of loose parts to a tightly fitted working machine. Assembly in 20F weather did slow things down a bit, there were times my digits became so numb bolts and nuts would fall through my fingers like fine sand in at a breezy beach.

 

The Stepper Driver:

For my setup, I found the best stepper motor driver to be the g540 by Geckodrive.

 

 

  • Four 10-Microstep motor drives
  • 0 to 3.5A rated phase current
  • 18VDC to 50VDC supply voltage
  • Mid-band resonance compensation
  • Auto standby current (70% current)
  • Short-circuit protected
  • Optoisolation on all LPT signal pins
  • Two 1A at 0 to 50VDC rated outputs
  • Four SPST to GND inputs
  • FAULT indicator LED,signal to PC
  • POWER indicator LED
  • I-SET resistor on motor connector
  • TRIM adjust for motor smoothness
  • Panel mount (5.7” by2.4” hole dim.)
  • Anodized aluminum package
  • No heatsink needed below 40C ambient
  • Easy to service, removable drives
  • Modular PCB design with no internal wires
  • 10kHz watchdog timer (charge pump)
  • Optoisolated analog output for a VFD drive
  • Conservative ratings, premium components
  • Comes with four backshells and four DB9 solder cup connectors

Several reasons why this driver is the the best for my setup: it supports high torque motors using up to 3.5A phase current, extra 4th axis driver for future expansion or if a primary driver fails, short circuit protection in case the wire are accidently removed from the drive, built in optoisolation LPT port to protect the PC from feedback, watchdog timer critical for E-stops, Mid-band resonance compensation saves a headache in the future, and if it driver fails the company is USA based and they can overnight a replacement for time critical production deadlines.

For the stepper motors are Keling KL23H2100-35-4B, 381OZ. The research indicated anything larger would be overkill considering I don’t intend to cut beyond the 200IPM speed.

 

Parts and Cost:

For those interested in possible going this route for their CNC machine here’s a part list and for an indication of the financial impact. These were my cost – prices will likely fluctuate.

  • FLA100 kit: 8020, fasteners, rails, motion system – $1300 + $73 S/H
  • Stepper motors: 3x Keling KL23H2100-35-4B, 381OZ/IN – $147 + $12.95 S/H
  • Motor driver: Gecko g540 – $299 + $13.75 S/H
  • Router: Porter Cable model 892, 2-1/4 HP – $165
  • Collet Kit: Precise 1/8″ 1/4″ 1/2″ collets, collet nut, spanner, lubricant – $87.95 + $15.37 S/H
  • Router mount plate: K2 CNC mount for PC 892 – $50
  • Wire – 30 feet – 18gauge, four conductor – $9.99 + S/H
  • E-stop – generic emergency stop switch – $9.99
  • Power supply – Meanwell S-350-48, 48V 7amps – $54.99
  • Hardware – extra bolts, brackets, and wood screws – aprox $28
  • Dust collection – pipes, clamps, adapters, brackets, blast gate – aprox $45 + S/H
  • Dust extractor – 120v 2HP, 1550 CFM, Harbor Freight #97869 – $139.99 (awesome sale price)
  • Supporting electronics – relay, fan, rheostat, receptacle, wiring, solder – aprox $13
  • Computer – PC, monitor, mouse, keyboard, speakers, cable, network – no price (all on hand)
  • Wood – 2x4s and plywood for the work bench – aprox $38
  • Table top – 3x sacrificial MDF table tops – $13 (sale price)
  • TOTAL : ~$2535

When it comes to cost there are a few notes to be made here. For one, while I had a working PC system on hand, a system with the right requirements would probably run $100+ used. Another consideration is software.  You will need a CAD program to draw up parts, then a CAM program to generate machine paths, then finally a machine controller to actually control the CNC stepper motors.

All the required assembly tools are staples among any shop such as socket set, allen wrenches, machinist square, dial caliper, solder iron, drill, plyers, miter saw, clamps, etc.

A big player in costs is the router bits. Generally, simple industrial production quality bits run $30 to $50 each. For starters, knowing I will probably break a few, I decided to go with a few cheap bits. After I learn more about tool paths, feed rates, spindle speed, and bit geometry, purchasing those expensive bit may be a worthy investment. Until then, $2 – $10 bits will work fine during the initial learning process.

 

Conclusion:

There are several modifications and additions on the to do list:

  • Dust collection
  • Cable management
  • Mechanical clamping system
  • Vacuum clamping system
  • Limit and home switches
  • Backlash tests and general alignment

Every step from napkin concept, detail designing, CAD programming, machine setup, machine operation, and to the final outcome is a blast. The ability to take an idea and turn it into a tangible reality in sometimes less than an hour is, for lack of a poignant phrase, kick ass!

 

UPDATE:

A few years after operating the machine chatter developed in the completed parts. The lead nut screw mounts became old and worn and after I replaced them with a better quality nuts the machine ran like new again.