My Makermade CNC Adventure: Calibration

My Makermade CNC Adventure: Calibration

MAKING ALL THE MISTAKES SO YOU DON’T HAVE TO

Up until the point of calibration, I had a few misadventures but mostly things went pretty smoothly. This is where it got bumpier. In the online assembly instructions on the Maslow forum, Step 6 was “attach sled to frame” and Step 7 was “calibrate”. So I started the calibration process with my sled attached to the frame.

As I extended the chain across the frame to measure the distance between motors, the position of my sled became more and more precarious until it was hanging in the air.

This seemed clearly wrong, but I couldn’t find anything specifically saying to remove the sled from the chains. It wasn’t until a few steps later that it became clear I’d need to not only detach the sled, but basically dis-assemble the whole chain/ pulley/ elastic cord setup that I’d just assembled, and then a few steps later redo it all. I’m not given to foul language, but I HATE re-doing something I just did. I’m all about the adventure of learning new things, but the second time around it’s not an adventure anymore, it’s just drudgery.

I found it really difficult to detach the chains from the sled while the weight of the sled hung on the chains. The first couple of times I had to do this, I had my 15 year old son hold it for me, but I don’t like being a helpless female, so I knew I needed another solution. I drilled a hole through the top center of my sled, and then through the top center of my top beam, and used an extra carriage bolt I had laying around as a hanger.

I’ll probably replace it later with a thicker bolt, but this made the whole process sooo much easier. I’m not ten feet tall, so a step ladder came in really handy, but it was such a relief to be able to just hang this and I hang it up each night now when I’m done in my shop just to avoid extra strain on the motor mounts, chains, etc.

Getting to the test cuts step was exciting- it was the first time I’d seen my Maslow in action! But as the picture shows, this step didn’t go smoothly. This was mostly user error. Here’s a summary:

Attempt #1 Didn’t realize I had to manually turn on the router
Attempt #2 Realized I needed to turn on the router, but turned it off between cuts while it traveled then forgot it back on
Attempt #3 Chain wrapped around sprocket
Attempt #4 Power supply came loose, lost connection
Attempt #5 SUCCESS!

This was a long and frustrating day- and did I mention it was an unseasonably hot day in Virginia with out 200% humidity? But every mistake I made helped me write a better assembly guide.

I changed the order of the steps, so that you install the Z Axis before calibration, and don’t install the chain/elastic cord assembly until after you’ve measured the chains. This feels like a smoother workflow, but let me know what you think.

Here are the mistakes NOT to make:

The Maslow automates a lot of the work, but you DO have to actually flip the “on” switch on your router

Putting the end of the chain behind the top beam, and shortening the elastic cord a few inches will cut down on chain tangling, but watch it when the sled moves to the top left and right corners. That’s when its most likely to tangle.

The connection between the power supply and the cord came apart a few times when I tripped over it, which halted the whole process and required starting over. So tape those two pieces together, and then tape the cord to the floor if it’s in a place where you might trip over it.

While we’re talking about the power supply and cords, the very first thing you should always check if your Maslow mysteriously quits in the middle of something is that everything is still connected. Just look at the Arduino on the back of your board. There should be TWO green lights shining out from it at all times. If one or both has gone dark, then your power supply or USB isn’t connected.

As prodigious as I am at making mistakes, I’m sure it’s not possible that I made them all. Please add your own “what I wish I’d known before I started” in the comments so we can make the assembly guide even better!

Assembly 1.5 Calibration

Click PDF image to download these instructions in PDF format

Tools Needed

  • Maslow CNC
  • Router, .25” bit
  • Safety goggles
  • Protective gloves
  • Screwdrivers

  • Power Drill, .5” bit
  • Hardware and components from kit
  • Computer or tablet
  • Ground Control software

Materials List

  • (1) 4×8 plywood, .75” thick*
  • (1) .5” carriage bolt

Calibration is the step that sets your machine up so it will cut designs accurately. Calibration is of paramount importance and is probably the most difficult, and sometimes frustrating, part of owning a Maslow. Because every user sets up their own frame, there are a lot of varying factors that may cause temporary hiccups. If you do get frustrated, take a break and come back to it.

NOTE: SLED/ CHAINS SHOULD NOT BE ATTACHED TO FRAME AT THIS POINT!

If they were attached previously, remove them before proceeding

Observe proper safety precautions, including wearing safety goggles and protective gloves especially anytime chains are attached and moving

STEP 1: OPEN GROUND CONTROL TO BEGIN!

STEP 2: CHANGE EXTEND CHAIN DISTANCE

  • Go to SETTINGS at top left of screen
  • Find Extend Chain Distance
  • Click MASLOW SETTINGS at top of screen
  • Click ADVANCED SETTINGS
  • Find EXTEND CHAIN DISTANCE, set to 1651
  • If using an alternate setup, setting should be a multiple of 63.5 MM, approximate distance from motor sprocket to where ring sled will rest in center of plywood.

STEP 3: CONNECT PORT

  • Go to ACTIONS->PORT
  • Click on the port that you set up previously when you set up the electronics
  • If you don’t see the correct port, click UPDATE LIST
  • Once port is selected, click CONNECT

STEP 4: INTRODUCTION

  • Read instructions,
  • Click BEGIN

NOTE: For a variety of reasons you may have to run the calibration process more than once. If so, there are some steps you can skip. This manual will give you guidance on which you can skip and which you can’t. YOU MAY ONLY SKIP STEPS IF IT’S NOT YOUR FIRST TIME CALIBRATING

STEP 5: CHAIN ATTACHMENT METHOD

  • If using the ring that MakerMade shipped with your kit, choose TRIANGULAR
  • If using a custom setup, it’s probably still TRIANGULAR

SKIP if you’ve done this before, and haven’t changed your setup. This is true for all subsequent “Skip” instructions.

STEP 6: DISTANCE FROM MOTOR TO PLYWOOD

  • Measure approximate distance from center of motor shaft to top of plywood, value will be fine tuned during calibration
  • CONVERT TO MM! 1 IN = 25.4 MM
  • Click ENTER MEASUREMENT
  • Enter measurement, click DONE

SKIP, if measurement hasn’t changed since previous calibration procedures

STEP 7: SET SPROCKETS VERTICAL

  • The goal is to get one tooth on each motor sprocket pointing straight up, 12:00 position
  • Buttons rotate sprocket to specified degree
  • CW = clockwise) CCW = counter-clockwise
  • Eyeballing is fine, just get it close
  • Click SET ZERO
  • Don’t use AUTOMATIC button

SKIP, if there have been no “location lost” errors in previous procedures or errors with chains skipping or tangling

NOTE: USE EXTEND BUTTON TO FEED OUT CHAIN for the following steps. Draping chains over sprocket manually then clicking PULL CHAIN TIGHT & MEASURE will not work.

STEP 8: DISTANCE BETWEEN MOTORS

  • Place first link of left chain on left sprocket
  • Click EXTEND
  • Left sprocket will rotate clockwise and feed out 100 mm of chain
  • Hold chain to make sure it doesn’t wrap around sprocket.
  • Change value to “1000 mm”
  • Click EXTEND 3 times more, still holding onto chain, keeping tension on it
  • Chain should now reach first link on right sprocket
  • If not, change 1000 mm value to 10 mm, click it until it does
  • Place end of left chain on right sprocket

STEP 9: SCREEN 5 MEASURING DISTANCE BETWEEN MOTORS

  • If value is still at 1000mm change to 10 MM
  • Click RETRACT until most, but not all slack is gone

CAUTION: during the next step, the chain may come off the right sprocket. It can be under a lot of tension and if it comes off, make sure you’re not within range

A carefully placed small piece of duct tape may provide some stability. Just be sure the tape doesn’t interfere with  movement of the sprocket.

STEP 10: SCREEN 5 MEASURING DISTANCE BETWEEN MOTORS

  • Pay attention to motors and frame during this time, if motors move or frame flexes, make adjustments to your frame so this doesn’t happen
  • Click PULL CHAIN TIGHT AND MEASURE. During this step, slack will be taken up and software will determine, distance between motors based upon how much chain is fed out.
  • Chain will slacken up when operation is done

  • Remove chain from frame, set aside until later

STEP 11: SCREEN 6: PICK CHAIN FEED ARRANGEMENT

  • If using default frame, Click CHAIN OFF BOTTOM

    SKIP- if you’ve done this before

STEP 12: SCREEN 7- REVIEW THE MEASUREMENTS

  • For future reference- jot down numbers, screenshot, or take a picture
  • If numbers look off, click back button to go back and redo steps related to any numbers that look off
  • If numbers look good, click LOOKS GOOD

SOME BALLPARK PARAMETERS FOR NUMBERS:

Distance btwn motors = <3048 MM if using 10’ top beam, <3568 MM for 12’ top beam

Vertical motor offset = # entered in Step  3

Kinematic type = Triangular

Chain feed type = Bottom

Rotation radius = 140 mm

Chain sag correction value =  varies

STEP 13: SCREEN 8- GENERATE CALIBRATION PROCEDURE

  • The machine is doing all the work here,
  • Take a deep breath, relax for a minute

DON’T SKIP

STEP 14: SCREEN 9- SET SPROCKETS VERTICAL

  • Same procedure as Step 4
  • This time it may work to hit AUTOMATIC
  • If it doesn’t work, don’t panic
  • Re-adjust sprockets with buttons as before
  • When sprockets are in place, click SET ZERO

SKIP only if chains are attached to sled because you skipped other steps

STEP 15: SCREEN 10- ENTER ROTATIONAL RADIUS ESTIMATE

  • Use numbers given on screen
  • Click ENTER MEASUREMENT and enter appropriate value for your kit
  • Click NEXT

SKIP- if you’ve done this before

STEP 16: SCREEN 11- ADJUST CHAIN LENGTHS

  • Place left chain on left sprocket as shown
  • Click ADJUST LEFT CHAIN while holding on to left chain to prevent wrapping
  • Left sprocket will turn counter-clockwise and extend chain to a determined length
  • Repeat with right chain

SKIP only if chains are attached to sled because you skipped other steps

NEXT YOU’LL ATTACH THE SLED TO THE CHAINS, LEAVE CHAINS EXACTLY WHERE THEY ARE

DO NOT CHANGE THEIR POSITION ON THE SPROCKETS!

STEP 17: INSTALL BOLT FOR SLED

BAG #2 pulleys, BAG #4 wood screws

  • Mark center front of top beam, about .5” from top edge
  • With .5” drill bit, drill hole in marked spot
  • Insert .5” carriage bolt into hole
  • Secure with nut

STEP 18: INSTALL PULLEYS FOR CABLES

BAG #2 pulleys, BAG #4 wood screws

  • Use center beam mark from Step 17
  • Mark 1” to the left, 1” to the right
  • Insert a screw through center of each pulley
  • Screw into marked spots

STEP 19: INSTALL CHAIN HARDWARE

BAG #4 wood screws

  • Mark 8” from end of top beam
  • Insert wood screw in marked spot on underside of top beam
  • Leave it protruding about .25”

STEP 20: PREPARE STRETCHY CORDS

BAG #2 stretchy cord, zip ties

  • Fold over end of stretchy cord 3”, fasten with zip ties
  • Trim ends of zip ties, repeat on all cord ends

STEP 21: ATTACH STRETCHY CORD TO FRAME

Bag#1 S hooks

1. Loop stretchy cord around center pulley

2. Loop one end of stretchy cord to screw under beam

3. Insert S-hook in free loop on other end of cord

4. Hook temporarily to same screw as first loop

STEP 22: ATTACH CHAIN TO MOTOR

BAG #1 small nails

PART #3 Chains

  • DO NOT CHANGE POSITION OF CHAIN ON SPROCKET
  • Pick up inside end of chain
  • Insert small nail through circular piece at other end of chain
  • Hammer into center of beam 8” from end

STEP 23: ADD CHAIN TO STATIONARY SPROCKET ON MOTOR

BAG #1 sprockets

  • Grab bottom of “u” of hanging chain, pull up and over nail towards center of frame
  • Place sprocket in loop of chain, holding onto sprocket and chain for next step

STEP 24: CONNECT CHAIN TO STRETCHY CORD

  • Hold chain and sprocket with one hand, grab s-hook from bottom nail with other hand
  • Insert s-hook through center of sprocket

STEP 25: ATTACH CHAINS TO SLED

  • Carefully hang sled on bolt in top beam
  • This is optional, but very helpful, as it may be impossible for one person to balance the heavy sled assembly while pulling the chains through the carriage mounts
  • A step ladder is also helpful here

THIS IS A GOOD TIME TO MAKE SURE THAT YOU’VE LOADED A WORKING PIECE OF PLYWOOD ONTO YOU FRAME IF YOU DON’T WANT THE TEST CUTS TO BE MADE INTO YOUR BACKING PLYWOOD

STEP 26: ATTACH CHAINS TO SLED

  • Grab dangling end of left chain, thread through hole in end of carriage mount
  • Insert cotter pin to fasten chain
  • DO NOT USE OPEN LINK AT END OF CHAIN, GO BACK TO LAST FULL LINK
  • Repeat with right chain
  • Gently lift sled off bolt and allow weight of sled to hang from chains
  • Sled should rest against plywood now

STEP 27: ADJUSTING THE RING

  • Router should hang vertically
  • If it’s tilted, loosen bolts on L-brackets
  • Move ring up or down on brackets until  sled rests against plywood without tilting away

STEP 28: MOVE SLED TO CENTER

  • Return to Ground Control screen
  • Click MOVE TO CENTER
  • Sled should move to center of plywood
  • Click NEXT

STEP 29: SET HOME POSITION FOR Z-AXIS

  • If Z-Axis is installed, make sure ENABLE AUTOMATIC Z-AXIS is turned on
  • Click ADJUST Z-AXIS until router bit just touches surface of wood
  • If Z-Axis is not installed, adjust bit depth manually
  • Click DEFINE ZERO

STEP 30: RUN TEST PATTERN

  • With router bit at zero, turn router on
  • Click CUT TEST PATTERN
  • The Maslow will now cut 5 shapes as shown

STAY CLEAR OF MACHINE WHILE PATTERN RUNS, IF CHAINS WRAP AROUND SPROCKETS OR ANYTHING ELSE HAPPENS, CLICK “STOP CUT” THEN TURN ROUTER OFF BEFORE TOUCHING CHAINS OR ANY OTHER MOVING PART

STEP 31: ENTER MEASUREMENTS

  • When pattern stops, follow onscreen instructions for measuring
  • Measuring distance and entering distance between cuts helps software dial in machine settings

STEP 32: REVIEW MEASUREMENTS

  • Same as STEP 7, if they look wonky, go back and redo steps related to numbers that are off
  • If they look good, jot them down
  • Click LOOKS GOOD

CALIBRATION COMPLETE!

NEXT STEP: BUILDING THE FINAL SLED

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