Major Surgery on a Build Plate

Update of 8-July-2017

Sanding your build plate is a lot of work.  There is a leveling technique that you should try with yours before deciding to pursue the atomic solution described here.  This technique has been described by Aaron Widmer on the Facebook group for the D7 printer and it follows here:

Take a piece of plain copy paper and lay it over your LCD screen (VAT removed) and push the screw posts through it so the paper lays flat on the screen. Loosen the 4 screws on the plate bracket so it is free to move (Do not install build plate assembly yet!). Home Z axis. When Z is finished homing, move the build plate to its highest adjustment position and attach build plate assembly and tighten to arm (While holding the plate so it does not lower and crash into LCD!). Gently lower the plate against the paper and apply slight pressure to make sure it is snug against paper and then tighten while applying the pressure. Move z axis up so you can install vat and start your first print.

If the above works for you then great!  If it does not and you still want to sand your build plate then read on.  If you do sand your build plate you will not need to follow the above procedure and can, in fact, level your build plate following the process that Wanhao advocates in their documentation for the printer.  Your build plate will also look a lot like the one used on a Form 2.  Maybe the Wanhao R&D team has one over on Formlabs ... but I kinda doubt it.

Original Post Follows

The good news is that Wanhao has made some great strides in reacting to feedback on the version 1.1 and 1.2 printers. Cooling and packaging in particular but a host of other things as well. The bad news is that they seem to be sending at least some customers build plates that are concave and painted with something slippery.

This is when I knew that I had a problem. Build plate should have had stuff on it! 100% casualty rate.

So I did a little bit of sanding. Clearly something is wrong here as only the corners and edges are being touched.

So I did a lot of sanding...by hand...with 80 grit paper. This is where I realized that getting rid of my 240 to 120 volt power supply and my yankee sander was going to be an issue. So I ordered a Black & Decker Mouse Sander.

See anything funny about this print? Since I had some down time I printed a build plate just to see if it would work. Extrusion lines!

Mine was printed using PET and it actually worked pretty well. Prints stayed on until I wanted to take them off.

Finally got the sander and a pack of papers from 60 grit to 800 grit and I walked through each one, a couple in come cases.

After hand sanding with wet emery paper from 1000 to 7000 we had 100% stickage. There is a problem on the left side but not a build plate issue.

Update of August 2017 - I did a second plate and stopped sanding at 800.  This last bit is overkill!

Instrumenting a 3D Printer for Heat Testing

My DLP printer experiment is as much of tinkerers panacea as it is anything.  And I am ok with that as I expected as much.  I have version 1.2 of the printer and version 1.3 has just been released.  The difference between the two is all a matter of cooling.  Which is to say that version 1.2 ran hot!  With that knowledge in hand I designed a new case for the printer with cutouts for some new fans. But will both fans be needed and if so what way should airflow run?  These are the questions that I would like to answer!

To be able to answer these questions I needed a quick and dirty way to measure temperatures within the printer.  It would also be helpful to know when the UV array is lit and how much light it is producing.  I decided to use one of my many Arduino' for this task connected to three thermistors and a photo resistor.  Initially I will use a bluetooth adapter to talk back to my PC.  I also want to source power from the printer so I need to convert 12v to 5v to operate the Arduino.

Here is a picture of what I built followed by a brief description of the various components.

1. Arduino Nano - Cheap as dirt on eBay but a capable little chip.
2. Expansion board for the Arduino Nano. Breaks out every pin on the board adjacent to power for whatever you want to connect.
3. Power converter to take the 12v from the printer supply down to 5v for these electronics.
4. Bluetooth adapter for transmission of data back to my desktop.
5. Thermistor (more below).
6. Photo resistor (more below).
7. Temporary 5v power supply.

The thermistors and photoresistor all operate in a similar manner.  Temperature or light change their resistance.  I create a voltage divider with the variable sensor as one of the two resistors.  By measuring the resultant voltage I calculate a heat reading for the thermistors.  The photo resistor reading is not translated but just used raw.  Here is the Arduino Sketch that runs on this device.

The output of the above sketch is a simple CSV stream of values that I capture on my Mac and then feed to a spreadsheet.  A sample of the CSV and a copy of the end chart are shown below.

Mods for my New Wanhao Duplicator 7 (D7) 3D Printer

Update of 9/5/2017:  Two of the designs that I mention here have now been extended.  The base now has a variant that houses the RPi under the printer.  In addition, the "Feet" now include an option to adjust the printer angle.

I have some good resin coming for my new printer early this week and have been struggling a little with the sample that came with the unit.  Not to mind, however, as I have used the time to make the printer a little more tuned to me.

The last and best thing that I designed was a base that raises the printer giving the fan more air flow while providing a place to mount the RPi that hosts NanoDLP.

http://www.thingiverse.com/thing:2268534

The RPi is housed in a really nice design also available on Thingiverse.

I did some other designs as well:

Cover for the resin tank.
Spatula based on the one that comes with the printer.
Device to help me level the build plate.
Handles 'cause mine did not have one and the damn thing is slippery.
Feet to raise the printer for better airflow.

All of my designs are licensed under the Creative Commons - Attribution - Non-Commercial license.

Eeeh Gads. Another 3D Printer!

I have been thinking about getting an resin based printer for a while but have not pulled the trigger for a number of reasons.  First, I really do not need one!  Second, I have seen the post processing work needed to remove the support structures that are required for this kind of printer and am not keen on them.  Third, I am space constrained in the man cave.  Fourth, they cost a lot of money for something that I really dont need!

As with all things in the technology space the prices, particularly at the low end, are coming down.   There are FDM 3D Printers now available for just a couple hundred dollars.  Entry level but fully capable of doing good prints.  This trend is also impacting resin based printers though until recently the lowest price point has been around a thousand dollars.

Enter the Wanhao Duplicator 7 which is aimed at the bottom price point in the market at 400 dollars.  The printer is extremely capable for that price point though.  The build volume is decent (120, 68, 200), the speed is decent (15mm-35 mm per hour), and the resolution is more than decent given that it can do layers of 35 microns and an x-y resolution of around 500 dots per inch.

And it is cute!  Its small size makes it perfect for the man cave.  I think the printer is a great demonstration of how the Chinese can take a product and develop a low cost version.  The electronics are based on a RAMPS board which is the same thing that drove the 3D Printer that I built two and a half years ago.  Everyone knows what they are and what to do with them.  The motor is the same as a zillion other 3D printers.  The power supply is a standard brick.  The LCD display is repurposed from what had been designed for a tablet.  i'm not sure what the video interface is but I would bet that it was repurposed from a laptop or something of the kind.  It is eloquent in its simplicity.

3D Printing and Scale Modeling - Recap of Selected Designs

This post is a "work in progress" summary of my favorite of the models that I have done over the past year or two.  Most of these models are available for download on Thingiverse and many have been discussed elsewhere on this blog or have an Instructable available.

One more note!  These are largely bespoke models crafted in Sketchup using its Pro features for solid modeling.  Those features don't make it the best 3D modeling tool out there but they help a lot ... and since I am an old dog that has been using Sketchup for a long time ... anyway ... the models are in Sketchup!

My Model	The Prototype
Curved Railroad Bridge and a Steel Pier
Retaining Wall
Concrete Railroad Bridge Pier
Ship - Cheated a little here as my prototype is a model from the Wrightsville Port N-Scale Layout!
Plate and Girder Railroad Bridge - Bridge No. 1276, Sideling Hill Creek Crossing
Bridge Fenders
xxx	xxx
Bascule Bridge
Windmill
Bailey Bridge [Thingiverse] [Blog] [Instructable]

Overnight 3D Printing - A Facebook Poll

I posted the following poll on Facebook and thought the responses interesting enough to summarize here.

Here is a summary of the results:

A strong majority of folks print overnight without concern. Another pretty large group prints overnight but with some concern. There are a fair number of folks that do not print overnight but the survey questions are flawed in that these folks could have reasons other than fire concern.

Some other observations. There are a number of people that have added fire detection and suppression with a variety of solutions mentioned from off the shelf, to external service provided, to self crafted. Finally there were even folks that admitted to having their spouse or boss tell them to pound sand on the printing all night thing. My other survey question asked if people had experienced a fire. A very large majority had not though a handful did. The fires described were all minor. Probably a bad survey question as someone that had a bad fire may not be doing the whole 3D Printing any longer! Finally, from comments on both polls, it seems like the concern is the highest with the cheap home built printers and diminishes as you go up market.

Cost and Appearance of Different 3D Print Resolutions

I had done a post some time ago comparing resolutions but thought that I would do another one using a model from a customer order.

600 micron nozzle with 300 micron layer height.  Time to print (each): 00:49.  Cost (for ten): 31.74
400 micron nozzle with 200 micron layer height.  Time to print (each): 01:10.  Cost (for ten): 41.17
400 micron nozzle with 150 micron layer height.  Time to print (each): 01:32.  Cost (for ten): 49.86
400 micron nozzle with 100 micron layer height.  Time to print (each): 03:07.  Cost (for ten): 62.90

Looking at the costs by time it would appear that my costing for the 100 micron layer print might need some adjustment (up)!

Time (Minutes)	Cost	Cost per Minute
49	£31.74	0.6
70	£41.17	0.6
92	£49.86	0.5
187	£62.90	0.3