The Deutsches Museum is one of the largest museums I’ve been to. There were so many topics on technology that the museum had. They had the usual topics on flight, ship building, engines, etc., but they had even more exhibits on classical mechanics, electromagnetism, chemistry, nuclear physics, mining, semiconductors, computers, cartography, microsystems, space exploration, printing, etc.

There was even a cool demonstration of arc lightning.

The section of space exploration was quite interesting too, but it wasn’t as big as the exhibit at the Smithsonian Museum of Flight.

The clean room exhibit reminded me a little bit of the type of work I did during my internship at Bosch.

Of course in any exhibit on computers, there has to be a computer from Remington Rand.

Here is the experimental apparatus that was used to discover nuclear fission.

The stuff I looked at was only scratching the surface of the museum. I pretty much skipped entire sections like time keeping, wind turbines, bridge building, among other things. I was there for four hours too and I didn’t even look at any one section in a lot of detail. To see everything, one would have to spend days here.

Link to photo album here

Print Volume

This is the amount volume that the printer is able to print in.  Generally, the measurement is given by the three dimensions of a rectangular prism.  The thing to watch out for here is that just because a printer has a large print volume, it does not mean the printer can reliably print in all of it.  Say the design calls for a thin flat plate.  If the plate is too wide, then the edges of the plate will peel/warp during the print and the flat shape that was intended will be slightly curved.  To visualize what warping is, imagine a flat plate lying on the print bed as it is being printed.  Warping is when the corners of the plate start peeling off the base during a print.  Warping will be explained in a little more detail later on.

Resolution

This describes the accuracy of the nozzle’s positioning.  It is usually measured in microns or inches.  Clearly a smaller value means that the printer will be more accurate in its position.

Layer Thickness

Because the printer works by extruding layers of plastic, thinner layers allow for more fine details.  However, more layers means that the part will take longer to print (all other things being equal).

Print Speed

3D printing is generally a slow process, but a faster print speed could definitely help offset that.

Nozzle Diameter

A small nozzle diameter means that the extruded plastic will be narrow and thus allow for fine details.  It also improves the smoothness of the printed object.

Ease of Removing Parts off the Platform

Because during a print, the base of the part (ideally) should be firmly adhered to the print bed, one must take care when removing the part from the print bed.  In some cases, removing a part requires a little bit of force to pry the part off the print bed.  This application of force may affect the alignment of the print bed relative to the nozzle.  In lower quality printers this can permanently affect the alignment or require frequent re-calibration   Seeing how “rigid” the print bed assembly can help assess how the machine accuracy can be affect during part removal.  For example, if the print bed is mounted on really large support structure, then the affect of misalignment is less of a problem than a machine where the print bed is mounted in a smaller support.

Enclosure

Some printers enclose the part to be printed in a box and some don’t.  The reason an enclosure exists is so that the machine is able to prevent the part being printed from losing too much heat during print.  Loss of heat during a print negatively affects the adhesion of the printed plastic.  Also a larger temperature difference means the part will warp more.  Without an enclosure, heat is able to freely transfer to the ambient.  High quality printers generally have an enclosure.

Variety of Printed Materials

A common material to print with is ABS.  Other materials such as PLA can be printed as well.  The use of the particular material can be quite dependent on the application of the printed part.  The cost of material also differs.  It is worthwhile to determine what material will be printed.  In many cases, ABS should be sufficient.

Warping

This is probably one of the biggest limitations of 3D printing.  Because of the use of heat during print, it is natural for the part to shrink as it cools down.  The problem is that the shrinkage is not uniform.  Some parts of the model shrink more than others and most of the time it is very unpredictable.  While there are some general guidelines that designers can follow to reduce warping, there are definitely some machine features that are good to have to help reduce warping even further.  Because the nature of the way the printer prints is that plastic is extruded layer by layer, the plastic layer at the very bottom is the first to cool down.  Cooling down means shrinkage.  This also means that as the bottom of the model shrinks, the printer is still printing on top of a slightly shrunken part.  Sometimes the shrinkage can be so bad that the part pulls itself off the print bed.  When the part is no longer securely adhered to the print bed, the part may slide around and ruin the entire print.  Warping is the enemy of 3D printing.

Below are some qualities of a machine that help reduce shrinkage:

• Heated print bed – a heated print bed keeps the plastic hot during the print and does not let the base cool down as much as if there were no heated print bed
• Enclosure – described above

There are more ways to reduce warping that the designer can do, but that is outside the scope of this article.

Number of Nozzles

A lot of printers just have the one print nozzle, but there are some with multiple.  This allows printing with multiple colours or in some cases printing with a water soluble support material.  Generally, support material has to be manually removed from the printed part, but if the support material is water soluble, this saves a lot of the manual labor involved in cleaning up the model.

Nozzle Maintenance

Through extended use, the nozzle can become quite dirty, that is black gunk starts building up on the surface of the nozzle.  If one is not careful, this can clog the print nozzle.  It is worthwhile to find out how often the nozzle needs to be replaced.  There are also other factors that may result in the need to replace a nozzle.  This is a recurring cost of maintaining the printer.  Some nozzles are cheaper and more common than others and it is worth it to see how often the nozzle needs to be replaced and how much it will cost each time.  Machines may come with extra nozzles.

Lubrication

Over time, moving parts may have to be lubricated.  Printers should come with a maintenance manual to help instruct the user how to do this.  It is also helpful to know the cost of the lubricant and how often it will be required.

Machine Lifetime Cost

Aside from the cost of the machine, operating a 3D printer can also incur the following costs:

• Shipping
• Insurance
• Brokerage fees
• Tools for removing support material
• Currency conversion
• Sales tax
• Print material (recurring)
• Replacement nozzles (recurring)
• Lubricants for moving parts (recurring)

As it can be seen, the extra costs can be quite significant.

Conclusion

Hopefully this has given a good general overview of some of the considerations in buying a 3D printer.  Different people will value different things in the printer and hopefully this subset of possible considerations for buying a 3D printer helps people make a decision as to what to look for in a printer.

Up until now, I’ve never opened an MMS successfully. My Internet settings on the phone were never set
probably plus I never bothered to do it. I also didn’t know the billing rates for opening them either.
But now, an opportunity arose for me to require MMS. The Deutsche Bahn has three options for distributing tickets purchased online. The first one is by printing them out, but I don’t have a printer. The second method is having them mailed to me, but that costs 3.50 euro. The third and best option, is to have them sent as MMS. Knowing that my phone, the P1i, has this ability, I looked for how to do it. After going through lots of Googling and reading through translated German sites, I finally figured it out.

Now, I use Vodafone in Germany, but this method may work on other providers even. I am also using GPRS, and not 3G (I don’t have a dataplan unfortunately). The way to do it is to register an account on Vodafone.de using your phone number. Obviously, if you use a different provider, you’d go to their website to make the account. I clicked through their services and found an option called the “HandyKonfigurator”. What it does is it sends me the proper settings required for my phone. I clicked through the dropdown boxes, found my phone and pressed continue. Vodafone then sent me a file that would inject the settings into my phone. They also sent me a PIN that I had to enter before my phone settings were changed. I did as I was asked, and now I can receive MMS messages!

Vodafone Internet Account Settings

• Address: event.vodafone.de
• No user name and password required
• IP Config and DNS Addresses are set to automatic
• Proxy Server: 139.7.29.17 at port 80

Vodafone MMS Account Settings

• Service Center Address: http://139.7.24.1/servlets/mms

1. Start > Run > services.msc or alternatively, type services.msc in the find box in the start menu
2. Look for the Print Spooler and stop the service
3. Once you stop the service, open the folder “C:WindowsSystem32SpoolPrinters”
4. Find the files with the date and time stamp of your print job and delete the files
   • if you are trying to delete a print job on a printer that is not directly connected to your computer, but on a network, the host computer may have to turn off their print spooler in order to delete the files
5. Retry printing

Usually for me, restarting the Print Spooler works well enough, but if need be, deleting the print job files works too.