Posts Tagged ‘ simplify 3d

# Overview

I’ve had the idea for sometime to create a new shelving unit in our garage:  When we moved it we tossed some spare Ikea shelves against the wall.  Wasn’t the best use of space.

Rather than go looking for a pre-built solution, I figured this would be a great learning experience:  Make an entire shelving unit from scratch, including all the parts that join it together.  At first I thought I’d use my X-Carve CNC for this, but after much research and though, I instead decided to create a new 3d-printed modular corner bracket system to hold 3/4″ plywood sheets together.  While creating it, more 3d printed items were needed, so I decided to coin the whole operation the “Modular Panel System“, or MPS.  As of this authoring the system includes:

• MPS – Corner Clamp
• MPS – Shelf Support
• MPS – Shim

This blog post describes the process I went through to create the MPS, how you can use them, and the shelving unit I designed to prototype it all with.

# Disclamer

This is all common sense, but because lawyers:  I am not responsible in any way for any type of accident, damage, injury, death, or cost incurred from using this system:  By downloading from any source and / or making these files on any printer / fabrication system, you wave me from from any liability now or in the future.  Be smart, use at your own risk, test.

You can download all the above-mentioned MPS 3d printable files on Thingiverse HERE.

# The End Results

Pretty pictures first:

Closeup of Corner Clamps in action

The final shelving unit installed, using the MPS.

# The 3d Printable Parts

All the 3d printable parts I printed on my C-bot.

## Corner Clamps

The Corner Clamps are what hold two pieces of plywood together at 90 deg angles.  By using them in different configurations, you can create just about any rectangular-shaped structure.

### Prototyping the Corner Clamps

I wanted an adjustable bracket to hold plywood together at 90 deg angles.  Since plywood can have varying width, I needed a solution that allowed for that slop.  I’d seen some interesting brackets at Maker Faire one year that did something similar, so I got to prototyping a system:  An outer L-shaped piece that could have an inner piece cinched against it, taking up any slack.  This was my initial prototype modeled in Autodesk Maya:

The idea is you put a nut in the outer L-shaped piece, and a screw through the end of the inner piece to hold it in place, and both sides press against the plywood.  Prototype was ‘strong like bull’ to humans, and my hope was the dense infill would provide the internal strength it needed, but I quickly broke it when torquing the held plywood.  However, it was still really strong, so I went about a redesign.

#### Stress testing, & Corner Clamp prototype 2

Based on where the cracks had formed in my prototype I redesigned it to use less material, but put what was there all in the right places.  From there I printed a number of them, assembled a small plywood box out of them, and started bouncing on top if it:

With only one bracket per side (less that in the above shots), four of them could easily hold my bouncing 180lb frame.  I found this encouraging.

#### Corner Clamp Final Design

At this point, I realized I had purchased 1/2″ plywood for my above tests:  For my final shelving unit I wanted to use 3/4″ ply, to provide more strength.  Because of this I went through one more iteration, requiring me to enlarge the brackets significantly to handle the increased width of the plywood:

#### Corner Clamp Dimensions

The below images show the overall dimensions of the parts in both inch and cm.  When I first started making them they had nice round numbers. But that very quickly went off the rails as design needs were encountered.

And to help with design, when two corner clamps are holding plywood opposite one another, the gap is just about 2″:

### 3d Printing the Corner Clamps

I print mainly in PLA:  I had used a couple different types during prototyping, and around that time I learned about MakerGeeks Raptor Series PLA : It’s supposed to be stronger than ‘normal pla’, and while I have no numbers to back up my findings, it does seem much stronger than ‘normal’ pla.  It’s more pliable, less brittle.  Based on that I bought 8 spools (enough I’d need to print the 100ish brackets, supports, and shims):

And got to printing:

#### Corner Clamp 3d Print Settings

These are the settings I used to print them in Simplify 3D, based on the Raptor PLA using a .6mm nozzle.  If you’er using a .4mm nozzle you’ll need to compensate for the layer height and number of roof\floor\shells.

• .6mm E3d-v6 volcano nozzle
• 300 micron z-height
• 90mm\sec
• 230c extruder, 60c bed.
• 6 floor, 6 roof, 0% infill.
• Based on my nozzle diameter, 4 shells completely filled all the structures.
• No raft, nor brim, no supports, did use a offset skirt.
• Be sure to print them flat, not up on one end.  They’re designed to be printed flat, to provide maximum strength based on those layer lines.

They came to 68g for both pieces, and took about 70 min.  Which means I could print 14 per 1kg spool.  So, I’d do 7 at a time on my c-bot’s 12×12″ bed: One over night and one while I was work (monitored via OctoPrint), allowing me to print 14 (one spools worth) a day.

Other notes:

• If during assembly you can’t get the washer or nut inserted, it’s likely your printer is over-extruding.  If it’s tuned properly, they should drop right into place with minimal to no pressure.

#### Corner Clamp Print Cost

I paid around 35$per spool for the Raptor Series PLA. For 68g of material, that works out to just about$2.40 per Corner Clamp for the raw materials.

### Corner Clamp Initial Assembly

#### Tools required

You’ll need:

You may want:

• An electric drill with 1/4″ bit.

#### Hardware required

I purchased all of this at my local “Orchard Supply Hardware”.

Per Corner Clamp:

• 1 Philips flat-head machine screw (or equivalent) :  1/4″-20 x 3″ – K
• 1 Hex Nut : 1/4″-20 – K
• 2 Flat Washers : 1/4″ – K

#### Assembly Instructions

• Insert a 1/4″ washer and 1/4″ hex nut into the L-shaped outer-clamp.  They should drop in easily.
• If they’re too tight to fit, there’s a good chance your printer is over-extruding.
• Insert a 3″ long 1/4″ machine screw screw through a 1/4″ washer, and insert that through the smaller inner-clamp.
• If it’s too tight to easily slide through, you can easily enlarge the hole with a 1/4″ bit on an electric drill.  I used this method often…
• Optionally you can simply thread the screw through the plastic.  This will give you more holding power (not sure if that is necessary though), but a lot more manual twisting.

• Push the machine-screw through the larger bracket, into the nut, and continue to tighten until the tip of the screw just pokes through the nut.  That should give you ample space to later fit the plywood in both sides.

## Shelf Supports

The Shelf Supports are used to hold up… shelves.  They are simply triangular supports that are placed under a flat piece of plywood, and screwed into the plywood being held by the Corner Clamps.

### 3d Printing the Shelf Supports

These are the settings I used to print them in Simplify 3D, based on the Raptor PLA.  If you’er using a .4mm nozzle you’ll need to compensate for the layer height and number of roof\floor\shells.

• .6mm E3d-v6 volcano nozzle
• 450 micron z-height
• 60mm\sec
• 230c extruder, 60c bed.
• 4 floor, 4 roof, 0% infill.
• Based on my nozzle diameter, 4 shells completely filled all the structures.
• No raft, no brim, did use an offset skirt.
• Supports are needed:  Since these are printed flat, and not on end (to give them max strength), you’ll most likely need supports to hold one of the sides up, unless your printer is a monster at printing bridges.

### Shelf Support Assembly

#### Tools Required

You’ll need:

• Philips Screwdriver (magnetic head is handy).

You may want:

• Electric drill with Philips bit (magnetic head is handy).

#### Hardware required

I purchased all of this at my local “Orchard Supply Hardware”.

Per Shelf Support:

• 2 Philips Flat Head Wood Screw (or equivalent) : 10 x 3/4″ – K
• 1 Flat Washer : 1/4″ – K

#### Assembly Instructions

• With the side that has the slot facing down, slide a 1/4″ washer up to the top of the support.
• With a screw on your driver, thread it through the washer, and into the plastic slot just until it catches.
• Just start the other screw into the other hold as well.  Note, not all supports need this screw:  I only usually have two per shelf.  They’re just there to keep the shelf from shifting one installed.
• You can leave it in this state until final shelf assembly.

Here’s how it looks assembled in place.  Note, the screw I have in the top is not what I reference above.

## Shims

Since plywood can have varied thickness, this can have an effect on the overall assembled shelving unit.  For Corner Clamps that hold vertical sections, I noticed they wouldn’t always touch the plwood under them, putting an unnecessary strain on their horizontal bits.  I designed these simple shims to be placed on top, or under a Corner Clamp, to help take up the slack, and help distribute the weight more evenly.

Here, you an see two shims in action, on place on top of a Corner Clamp, and the other underneath one:

### 3d Printing the Shims

Just print them completely solid.  I made a bunch and used them liberally as needed.  You can make your own by taking what I provided and scaling it by any amount in your slicer software (presuming it has that ability)

# Garage Shelf design

This section describes the shelf I designed that made use of all the above Modular Panel System pieces.

## Digital Design

At the same time I was designing the Modular Panel System, I was also designing the shelf to prototype it on in my garage.  I used Autodesk Maya for this : Yes, there is probably much better software out there for this sort of thing, but I know Maya best, so it was the software of choice.

After measuring my space, I went about mockup up what I’d think the shelving unit would look like in 3d:

All the solid pieces are what will be assembled using the Corner Clamps, and all the gray-outline ones will be held with the Shelf Supports.

## Plan Creation

After I (and the Mrs) was happy with the design, I did a manual space-fitting operation in Maya:  I laid all the panels down into shapes that match 4’x8′ pieces of plywood.  This both let me know how much plywood I had to buy, and how to make all my cuts.  Since the Mrs asked that all flat pieces were pained white on top, I also called out that in my plan:

This also led to some design changes:  I had some shelves that were just over 4′ long:  If I could make them fit 4′, then I could maximize my material.  Based on that, I deduced I needed 9 sheets of plywood.

## Cutting & painting the plywood

I ended up getting 3/4″ sanded pine plywood.  Has a nice smooth pine veneer on both sides that required no sanding on my part.  9 sheets @ $30 a sheet =$450 in plywood.

Based on my above plans, I’d measure out each cut, and get to it with my circular saw:

4+ hours later, I had this pile:

Which the boy and I spent a couple hours sanding all the cut sides on.  Whew…

From there, all the horizontal parts got laid out on plastic in my yard, and I rolled on the paint:

A few days later the paint had dried, and final assembly could ensue…

## Garage Shelf Assembly

It took a whole weekend to just get rid of all the existing stuff on that wall of the garage.  So the next weekend, with the occasional help of my wife and son, the new shelf was assembled.  Guessing it took around 6 hours, which included extra fabrication like cutting holes for electrical plugs, and other gotchas.  But for the most part it wen off without a hitch.  To do something this size, and extra pair of hands is really handy.  BTW, 3/4″ plywood is… heavy.

Special note : Before assembly, I used my stud-finder to figure out where on the wall the studs were:  On the large, back-pieces of plywood facing your, I used 3″ wood-screws to anchor them directly into the studs post-assembly.  I’m in California, earthquake territory.

### Installing Corner Clamps

This was the method I used:

• It will vary based on what section of the shelf you’re assembling,but the general process goes:
• Make sure the machine-screw is loose enough so you can get plywood on either side of the clamp.  Or, if you’re attaching a clamp to an already assembled section, you can completely unscrew it, put the pieces on either side of the corner, and then re-thread the screw.
• I use a screwdriver to tighten it up:  I watch the plywood on either side “suck” up into position.  While tightening, I make sure the plywood is pressed up flush against the middle of the bracket, so there’s no gaps exposed.
• On a large section with many Corner Clamps, I’ll leave them all slightly loose until all are in place, square up the section, then tighten each one.
• Don’t forget to add shims in where needed, before you tighten everything up, and before you put a load on the shelf.

#### How many Corner Clamps to use per section?

For the above shelving unit, I used two Corner Clamps to hold each side of each section.  For example, for the middle desk table by the chair, it had two clamps on the left, two on the right, but based on it’s length, three on the back.  It’s all based on the sizeof the shelf, an the load it will be holding.  If in doubt, add more.  You can always safely add more.

#### How tight should I make the Corner Clamp?

Tight enough, but not too tight?  I never actually broke one from tightening, but very quickly I got a feel for how tight I thought it should be.  If you hear it start to crack either you’ve tightened way to much, or you have a bad print.

### Installing Shelf Supports

This was the method I used:

• I first marked where the top of each Shelf Support should be.
• With the screw just barely poking out the back, I held the Shelf Support in-place on the wall, and used my screwgun to tighten it up.

#### How many Shelf Supports should I use per shelf?

For the above shelving unit, I used two on either side of each shelf, and 2-3 on the back based on their length.  Again, it’s entirely based on what they’ll be holding.  If you’re going to fill them with books I may place one ever 6″.

#### How tight should I make the Shelf Support?

For the screw that goes into the wall, through the washer, I cinch it up with my drill until I can no longer twist the bracket back and forth.  For the screw that goes up into the piece of wood above it, this can be left nearly loose:  I tighten until the screw head his the plastic and I stop.  If you over-tighten that one, you can split the bracket.  And it doesn’t need to be tight to do its job.

## Total Shelf Cost

Rough figures:

• 9 Sheets of plywood at $30 a sheet:$270.
• 8 rolls of filament at $35 a roll:$280.  Used nearly all of it, but that’s also counting print failures that happened as well.
• Various nuts, bolts, washers: $30 (estimate) • Can of paint:$15.

Total:  Just under $600. # Final Thoughts Was a great experience. Was a lot of work. Was hopefully cheaper than buying Ikea shelving As of this blog post the shelving has been installed for three weeks, fully loaded with stuff, and nothing yet has broken. It’s my hope you can uses these files, tools, and ideas to aid in your own creativity. And always, be safe! ## C-Bot: Taming the Volcano’s print settings The C-Bot has been a lot of fun to play with. And slightly dangerous: “Quick” five hour prints can easily cost close to$20.  And while it’s been good at printing large vases and shelves, I’ve not been happy with it’s small-scale detail.  The biggest problem is the 1.0mm E3D-V6 Volcano nozzle leaving blobs all over the place.  But after a good… 12 hours of making test prints, I’ve finally got it to a place where I’m starting to get happy with the results (based on my initial settings discussed here).  Below I’ll walk though the details.

All of the vases and shelving I’ve made (here, here, & here) have been printed at 45mm/sec, in PLA, at 250 degrees.  Which is way to hot for PLA, but I learned that when slicing in Simplify3D’s ‘vase mode’, at that speed, if lower temps are used, the print will delaminate into a slinky when done.

For whatever reason, 45mm/sec was a very important speed in my head, so I spent days trying to calibrate the nozzle at that speed.  But it’s been hard.  So finally today I brought it back to 30mm/sec, and finally, with a ton of fiddling, got some good results.  The slicer terms I discuss below are based on Simplify3D‘s settings.

Compare prints A & B (500 micron layers you see there), each 40mm across:

Same model, same orientation, different print settings.

For the life of me, I couldn’t get rid of all the zits on print A:  Even though I had retraction enabled, whenever the hotend would come to the end of a segment, I could physically see a bit of filament extrude out.  No amount of additional retraction, ‘wiping’, ‘coasting’, or ‘extra restart distance’ would solve the problem.  Finally, in the ‘Advanced’ tab, I checked on ‘Perform retraction during wipe movement’, and print B was born.  At this point I easily had a small bucket full of test prints, so I was pretty happy, and may have lol’d a bit.

From there, I gave the Make 2012 Torture Test a try again:  I’d done it before, and… I didn’t take a pic, it looked like my printer had thrown up all over the place.  So while the below image looks pretty sketchy compared to some finely-tuned .4mm nozzle machine printing at 100-200 micron, for this beast, I’m pretty happy:

(Note, I intentionally didn’t show the back : The rainbow arch did fail.  But it almost made it… )

Based on all of that, here’s the highlights of the Simplify3D settings:

Material:

• Gizmo Dorks Gray PLA, printed on glass covered in wood-glue slurry.

Extruder Tab:

• Nozzle Diameter: 1.0
• Extrusion Multiplier: 0.9
• Extrusion Width: Manual : 1.0
• Retraction : On
• Retraction Distance: 10mm
• Note, the “E3D-v6 Troubleshooting Guide” says not to use retractions over 5mm, since they can pull the filament into the cold-zone.  But this is for their default (smaller) nozzle\hotblock, and the Volcano is already 10mm longer than it, so a 10mm retraction has been working ok.
• Retraction Speed: 60mm/sec
• Wipe Nozzle: On (This pairs with the wipe setting in the Advanced tab, below.  Weird they split the settings into multiple tabs…)
• Wipe Distance: 3mm

Layer Tab:

• Primary Layer Height: 0.5mm
• Top Solid Layers: 3
• Bottom Solid Layers: 2
• Outliner/Perimeter Shells: 1
• First Layer Height: 75%
• First Layer Width: 110%
• First Layer Speed: 75&

Temperature:

• Extruder: 210c
• Heated Bed: Off

Coolling:

• Fan turns on, on layer 3.

Other:

• Default Printing Speed: 30mm/sec (printing at faster speeds requires hotter print temps to get the filament melted in time)
• X/Y Axis Movement Speed: 60mm/sec
• Filament Diameter: 1.75mm (as measured, pretty spot on)

• Only Retract When Crossing Open Spaces:  Off (this speeds things up, but lowers outer shell quality when only printing with one shell).
• Force Retraction Between Layers: Off
• Perform Retraction During Wipe Movement : On (this is where the magic happened)

So now that I have it working at that speed, next up will be to see if I can get similar positive results, but faster!

## Building the C-Bot 3D printer: Part 24 : Tuning print settings for the Volcano

(Note:  Since I authored this, I have updated  Volcano print settings blogged about here)

Now that the cooling fans are installed and I can start tuning my print settings.  I’ve been using a .4mm nozzle on my Replicator 1 for the past 3 1/4 years:  The nozzle I have installed on my E3d V6 Volcano is 1mm (currently:  I have other nozzle sizes from .6mm -> 1.2mm).  And getting this thing to print right has been… much different than I’m used to.  Mainly first layer adhesion.

I spent the bulk of this 4th of July printing off a variety of 1 and 2 cm calibration cubes getting things tuned in.  Below are my current findings on what makes the Volcano happy using my slicing software, Simplify 3D.  Note, I’ve been searching all over the web for ‘volcano print settings’, and really haven’t found anything.

• Print surface:  Removable glass plate on heated bed.  I mix 1 part wood glue with 1 part water, use a paper towel to slather the glass.  After that dries, do it again.  PLA loves to stick to it.  I’ve gotten far better results with this than blue painters tape.
• Filament:  “Natural” PLA, 1.75 mm, manufactured by Esun.
• I also use a ‘filament-cleaner’:  Sponge soaked in some vegetable oil the pre-extruded filament is pulled through before it hits the Bowden drive.  I’ve had good results on my Replicator 1 using these.  Note:  Do not over-soak!  I ended up with a pool of oil on my build platform nothing would stick to
• Notable Slicer Settings:
• Layer height:  500 micron/.5mm : Half the width of the 1mm nozzle.
• Print speed:  30mm/sec.  Just a starting point.  I’ve gotten good results with up to 45mm/sec, but around 60mm/sec (based on the below settings) print quality starts to suffer.  This sounds terribly slow considering I can get good results out of my Replicator 1 at 120mm/sec, but it’s weird to think this thing still prints faster:  A solid 1cm calibration cube takes 2 minutes.  A solid 2cm cube takes 8 minutes.
• Extrusion Multipler : Set to .9:  Normally on my Rep1 with a .4mm nozzle I leave this at 1.0 for PLA.  But it seems the bigger the nozzle the more it wants to over-extrude, and I’ve found success with this value.
• Extrusion Width : 1.0, the same as the nozzle width.
• Retraction:  Had a lot of issues with the nozzle drooling all over the place, but based on these settings it’s behaving much better:
• Retract distance: 10mm
• Retract vertical lift : 0 : I had set this to .25, but the constant lowering/raising of the bed caused too much commotion for my taste
• Retraction speed : 45mm/sec
• Coast at end:  Off.  I had set this to .5mm, which worked good on calibration cubes, but on larger prints with a single shell, slight gaps started to show up.
• Wipe Nozzle : Off.
• Ooze Control Behavior:
• Only retract when crossing open spaces:  True
• Force Retraction Between Layers : True : This is important, without it, blobs would show up on the perimeter.
• Only wipe extruder for outer-most perimeters : True : Only matters if you’re doing ‘wipe’ (which I currently have disabled).
• First Layer Settings : These were really important to get right:
• First Layer Height : 75% : Anything less than this would squish the filament too much, and cause it to overlap/delaminate corresponding extrusions.
• First Layer Width : 90% : Larger values contributed to the above issue.
• First Layer Speed: 50%
• Temperature:
• Extruder: 200 deg
• Heated Bed : 60 deg : Event though this is PLA, heating up the bed really helped the first layer stick better.  Without heating the bed, the extruded filament would just sort of ‘bounce’ off the platform, curling up into the air.
• Cooling : Turing on the filament cooling fans starting at layer 2.  Note, so much filament is coming out, I think I need more powerful fans… even with two I think it could be cooled down faster.

Based on those settings I was getting calibration cubes printed within five-hundreths of a mm tolerance, not too bad IMO.  I was also able to successfully knock out single and dual-shell cube prints with a variety of infill that feel strong enough to drive a car over.  Really looking to printing something ‘big’!

But in the meantime, the 2cm calibration cube’s aren’t looking so bad either:

2cm cube, 500 micron, courtesy of the Volcano

## Building the C-Bot 3D printer: Part 21 : Software Day 4: PID Autotune & start/end G-Code

Total time : 2.5 hours

Even though I need to really un-spaghetti the machine and do the final wiring, I can’t help but want to print more, especially since I installed & tuned the DRV8825 stepper drivers:  I want to make sure they actually work!

### Start & End G-Code

At the same time, I wanted to create better start & end G-Code for the bot:  I slice & print using Simplify 3D (S3D):  When you create a new custom printer profile, for the start G-Code, all it does is a G28:  Auto-home.  It seems to take care of the extruder and bed heating for you.

In addition, even though I’d previously figured out how in S3D you can set ‘global G-Code offsets’ in its G-Code tab, which lets you define the offset between home and the build platform, I thought it’d be better to set it in the start G-Code instead. I don’t know why, but it feels safer in there…

I’ve never done any start\end G-Code ‘programming’ before. The start/end G-Code for my Replicator1 was already setup.  So heading off to the ‘G-Code in Marlin‘ page, I researched what I wanted it to do on start:

• Lower the bed a bit just in-case it hadn’t before
• Home all axes
• Warm up the extruder (and eventually heated bed)
• Purge the nozzle
• Move nozzle to edge of the bed and zero it (per the above paragraph).
• Start print

And on end:

• Turn off extruder and bed heating
• Lower the z-platform slightly
• Home XY
• Disable motors

Another great resource is S3D itself:  Once you’ve connected to your machine, and are in the Machine Control Panel, any commands you issue show up in the Communication log:  So I set about doing each step manually, then creating the G-Code script for them.

What I came up with is currently below.  I’m sure this will change in the future.  But just in case my computer explodes I’ll have a backup here.  Note that [stuff in brackets] is S3D’s own internal syntax for embedding variables to help make the gcode more temperature agnostic.  Pretty nice.

Start G-Code:

G92 Z0 ; Set current z position to zero.
G1 Z20 ; Lower Z to be safe 20mm.
G28 ; Safe Homing of All Axes
M104 [extruder0_temperature] T0 ; Set extruder targe temp
M109 S[extruder0_temperature] T0 ; Wait for extruder current temp to reach target temp.
G1 E50.0 F600 ; Purge nozzle 50mm at 10mm/sec
G92 E0 ; zero extruder
G1 X2 Y26 ; Move nozzle to left front corner of build platform.
G92 X0 Y0 ; Zero X & Y here to start the build.

End G-Code:

M104 S0 ; turn off extruder
M140 S0 ; turn off bed
G92 Z0 ; Set current z position to zero.
G1 Z10 ; Lower Z to be safe 10mm.
G28 X0 Y0 ; Home XY
M84 ; disable motors

So I fired off my first print over USB, and ran into all sorts of weird problems over the next hour.  Long story short:

Gotchas:

• Every time I change a setting in S3D and want to re-print, I need to turn my printer off and on.  I don’t know if this is a S3D bug, a Rumba bug, a Marlin bug, or what.  But if I don’t do this, the start G-Code won’t properly execute.  Side effects include it not heating and immediately starting a print, or heating up but then never beginning the print after it.
• Once that was resolved, for the longest time I couldn’t get the filament to stick to the bed:  it would just curl up around the extruder.  I finally realized that a new profile I’d setup had my layer height set to 200 micron… printing with a 1mm wide Volcano nozzle:  Once I set that back to 500 micron the printing had no problems.
• I really need to get a print-cooler fan installed:  I built a custom one for my Replicator 1 which has really helped.  When I finally got my printing working, and was working on a 2cm test cube, the sides looked pretty good for effectively my second print:
• But when it got to the top, the whole print was so hot that the extruded top layer filaments literally started grabbing & collapsing the side-walls.  Plus when I went to remove it when the print was done, it was soft like warm gummy bear:
• Top priority: Get print cooler fan installed.  Or maybe a jet of liquid nitrogen….

### PID Autotune:

Update:  Since authoring this post I have switched my electronics to RADDS, and my firmware to Repetier.  See the “Part 31 post” for the latest on it.

While my extruder has been heating up fine, I noticed that as it approaches the target temp (say, 200c) it really slows down for the last few degrees, and takes a long time getting to the final temp.  I remember that when I switched my Replicator 2x to Sailfish firmware, the extruders stopped heating up correctly, and talking on the forums they told me I needed to update my PID settings.

PID stands for “proportional-integral-derivative“, something I did not learn about in math class.  But in a nutshell it’s a way via the maths to reach a target value smoothly and quickly, without banging/oscillating all over the place.  And luckily, Marlin comes with a PID autotune feature you can run as G-Code directly from S3D (or any software that can issue G-Code):

M303 E0 S200 C8

Fire that off when you extruder is cold, and a few minutes later it’ll spit out something that looks like this:

Recv:  bias: 213 d: 41 min: 199.38 max: 200.71
Recv:  Ku: 77.96 Tu: 13.40
Recv:  Classic PID
Recv:  Kp: 46.77
Recv:  Ki: 6.98
Recv:  Kd: 78.32
Recv: PID Autotune finished! Put the last Kp, Ki and Kd constants from above into Configuration.h

And those values you then enter back into Marlin’s Configuration.h file.

These were my original values when I authored this blog post:

#define DEFAULT_Kp 46.15
#define DEFAULT_Ki 5.10
#define DEFAULT_Kd 104.32

UPDATE (2016-01-13) :  But I found when my powerful 24cmf cooling fan would kick on to cool the Volcano nozzle, the temp would drop, and it would take a loooong time trying to catch back up.  So instead, I cranked my fan to 100% (255) and re-running the auto-pid gave me the values in the code snatch two paragraphs up.

I never timed the nozzle warmup before, my E3d-V6 Volcano now heats up from cold to 200c in 2min 10 seconds:  Not too bad.

I’ve still not got my heated bed soldered up yet (waiting on 10-gauge wire in the mail), but I’ll run this again on the bed when it’s ready.

## Building the C-Bot 3D printer: Part 19 : First print!

May as well show the good stuff first:

Even though the electronics still look like a giant pile of spaghetti out the side of the bot, there wasn’t much left stopping me from actually printing something.  But, a few things still needed addressed:

• My build-platform wasn’t remotely level, it was drooping way too much on the front.  With the help of my wife and son, I loosened up all the bolts holding the cantilevered 20×40 beams to the Z-stage, had my son slightly lift up on the end of it, and I re-tightened everything while my wife helped hold a wrench on the rear of the nuts where needed:  That got me able to level it with some z-endstop adjustments.
• Based on where the hot-end homes, there’s a 2mm X & 25mm Y offset from the corner of the build platform (calculated my manually moving the toolhead on X&Y via the LCD to the corner of the build platform).  I couldn’t figure out where in Marlin to enter these values:  Obviously the head needs to move to this position from home and ‘start’ the print there, as 0,0,0.  I slice using Simplify 3D, and I finally found these offsets in the “G-Code” section of the Process window, under “Global G-Code Offsets”.

I also needed to configure Simplify 3D to actually recognize this machine:  Luckily version 3.0 came out just yesterday, and has a new machine ‘Configuration Assistant’ that made the process of ‘building’ my machine pretty easy.

From there, I imported a simple 1cm calibration cube, slapped some blue painters tape on my build platform, and fired it off.  It’ immediately started moving, but not extruding:  Come to find out, even though I had all my stepper wiring in the Rumba the same, I had to flip the harness on the Bowden extruder 180 to get it to extrude the direction.  With that resolved, take two worked flawlessly:  A few minutes later, a tiny 1cm cube appeared:

1st print!

This was printed with a 1.0mm E3d-v6 Volcano nozzle, at 500micron layer height.  Beefy!  Surprisingly using my calipers, it was within .02mm tolerance on all axes:  Not bad for a first print!

Safe to say I’m pretty happy that it ‘just worked’ on the first try.  Now that I know it works I’m going to clean up all the wiring next, then get into the print calibration phase.