3D Printing Technology Blog

"Instant" quoting versus hands on "Online quoting"

Some rapid prototyping services offer "instant" quoting where you upload your 3D Stereolithography files and you receive an instant price quote.  However, most Rapid Prototype, or 3D Printing service providers have an "online quoting" page on the website and "online quoting" should not to be confused with "instant" quoting.  The "Online quoting" process takes your uploaded file and puts it directly in the hands of a person who accurately quotes your job per their standards then sends you a printed quote.  "Instant" quoting takes your uploaded file, scans the volume that exists within a box that surrounds the entire part, then issues an instant quoted based on the volume inside the box.  There may be empty space within the box that the 3D model doesn't occupy that you are paying for.  If you used the instant quoting services before, you have probably noticed that when you upload larger, or complex parts, you don't get an instant quote right back.  This is because the larger, or more complex parts require personal attention to perform an accurate  quote.  I am not a recommender of "instant" quoting because I don't see it as an accurate method to qualify a job and I have seen large differences in quoted prices from "instant" quoting services and they are always higher than a quote from the more accurate "online" quoting method.  Instant quoting is more a marketing tool.  Real hands on analysis of every job is needed to accurately quote a 3D Model.  See example here:

"Online quoting" services for rapid prototyping and 3D Printing offer the accuracy needed because of the human factor involved.  We take your rapid prototype project and place it into our rapid prototype OEM application software where the entire 3D model is scanned, the surrounding box empty space is ignored, and an accurate material usage and build time is displayed to the analyst performing your quote.  Online quoting doesn't take much time, so just because a rapid prototype service doesn't have an "instant"  quoting service, don't be alarmed, but rather be assured you will receive an accurate quote.    

PolyJet Vero Blue used as extreme Rapid Manufacturing

Kaiser3D recently produced a functional actuator gear assembly made from PolyJet Vero Blue at an extreme cost and time saving to a customer who needed 30 of the parts within 2 days.  The rapid prototype part was cylindrical in shape and stood 2" tall and was 1.5" in diameter.  The customer requested this 3D model as a totally functional replacement for a more expensive aluminum part.  The aluminum part had to be polished after production in order to meet the same surface resolution of the PolyJet rapid prototype that came straight out of the 3D printer.  This was needed in order to prevent jamming during movement of the actuator gear performing a mission critical function.  Not only did the high resolution PolyJet Vero Blue part perform just as well as the more expensive aluminum part, Kaiser3D shaved 10 days off the customer's waiting period and saved the customer over $1,700.00.  Because the PolyJet 3D functional model had the capability to withstand absorbtion of water, it performed excellently when exposed to weather conditions of high humidity, then a short time later, operating at high altitudes in extremely low humidities and severe cold.

This success story is only one of many where Rapid Prototyping, or 3D printing, is used as an alternative to Rapid Manufacturing.    

Where is 3D printing applicable? Is it Rapid Prototyping?

Lets be clear; 3D Printing is Rapid Prototyping, but not all Rapid Prototyping systems are 3D Printers.  A printer type rapid prototype system "jets" liquid material out of spray nozzles located in a block, laying down a 2-Dimensional bitmap, one on top of another at specified mechanical heights, or jets liquid out of the block into a material like a powder that absorbs the liquid and solidfies the powder into a hard bitmap image.  I have been involved with Rapid Prototyping and Manufacturing since 1993 and the term applied to the industry was "Rapid Prototyping".  Objet Geometries was the first company to coin a rapid prototype system a "3D Printer" and called their rapid prototype system technology "3D Printing Technology".  It was the first high resolution rapid prototype system to enter the arena with surface quality of parts containing RMS values in the Die casting range with the capability in Full Glossy mode of RMS values in the lower Die casting range.  See here:     

 

How can a 3D Printer create such smooth surface resolutions?  Simple, a 3D Printer grows layer after layer in very small slices of 6 ten thousands of an inch .0006" and has the ability to deposit material with excellent precision.   

Laser scanning a valuable tool in conjunction with Rapid Prototyping

Laser Scanning is a non-contact technology that digitally captures the shape of physical objects using laser light. A laser probe projects a line of laser light onto a surface while cameras continuously triangulate the changing distance and shape of the laser line as it sweeps along, digitizing the object in three dimensions (see below for more information about laser triangulation).

Laser triangulation is an active stereoscopic measurement technique that computes the distance of an object with a directional light source and a video camera. A laser beam is deflected from a mirror onto a scanning object.  The object scatters the light, which is then collected by a video camera located at a known triangulation distance from the laser so that the 3D spatial coordinates of a surface point or line are calculated.  The CCD camera’s 2D array captures the surface profile’s image and digitizes all data points along the laser and can be seen here: 

Overview of 3D Laser Scanning, Dimensional Inspection & Long Range Scanning

Rapid prototyping steps in when the scanned output data is saved as a stereolithography file solid CAD file.  This file can then be created into a physical 3D model for analysis via use of rapid prototype 3D printing technology.

Repeatability of 3D Printer rapid prototype systems

Rapid prototype system manufacturers normally state one specific tolerance the part measurements should never exceed across the surface of a 3D model. From experience, a critical dimension on a part may measure +/- .002" off dimension on one side of part, while on the other side, a dimension may measure +/-.003", .001", or .000" etc. The overall reason for this is what is termed "repeatability".

System repeatability speaks to the mechanics and software programs of automated manufacturing equipment and critical subsystems within whole systems.  Some manufacturing systems have better critical dimensional accuracy capabilities than others.  For example, I'll use a laser traveling across a build area of one foot in the X plane (left to right, or right to left).  That laser energy beam looks nice and smooth as seen by the human eye as it draws a bitmap image of a certain depth (layer height in the Z axis) into the medium (powder in this case). What we can't see is that the laser is not actually traveling smoothly, but it is most likely traveling within acceptable parameters specified by the manufacturer and meets the manufacturer's definition for repeatability.  It stops and starts (shutters) a little in it's travel and deviates off a straight line a little here and there. The key to good quality of 3D models being produced on a rapid prototype system is to have performance of critical subsystems meeting repeatable performance standards throughout production.  

There are deviations in all axes on all manufacturing systems, some systems with better repeatability than others, even though the system may be the same model and manufacturer.  For this reason, it is CRITICAL to have good and knowledgeable Field Support Engineers supporting your systems.  In the Field, I have never seen a PolyJet part measure more than .005" off actual dimensions in all axes and normally measures no more than +/-.001" to .0025".  A maximum dimensional tolerance number is issued by manufacturers as a baseline tool for Field Engineering and Applications of what to expect and target.  State of the art software applications have increased repeatability excellently over the last 10 years in Rapid Prototyping and other manufacturing systems.  In reality, a manufacturer states a maximum tolerance value average that is normally very high and all systems can be tuned to degrees of calibration for tolerance values of normally +/- .005" and less.  Again, it is a baseline number. But in general, the PolyJet 3D printer system produces impressive dimensional accuracy and is the most "repeatable" rapid prototype system I have encountered because it is a 3D printer system.

Critical importance of shells in CAD files for 3D printing

A 3D Stereolithography (STL) file must consist one single shell when complete unless the file contains extra features which are intended to move within the part.  An example of a Stereolithography file for rapid prototyping with two shells would be a whistle with ball.  A file with three shells would be a part with two moving gears inside it.  If a single solid part with no moving parts has more than one shell, then the part can have a hole in it when complete and render the part unacceptable.  If a rapid prototype service provider does not have a method for verifying integrity of Stereolithography files, then the service provider can't guarantee quality and integrity of the part.  PolyJet rapid prototype 3D printers jet the gel-like support in voids in the 3D models, and when washed off during post processing, the voids will be evident.  If a file is real bad, entire features will separate from the prototype.  I have received Stereolithography files in the past that consist of more than one shell and they are one solid mass part but consist of a number of Stereolithography files meshed together to form one.  I have not had problems producing these rapid prototypes. 

I strongly recommend designers purchase a Stereolithography file checking software.  I recommend Magics RP made by Materialise.  They sell Magics RP Lite that has file checking capability and is less expensive than their full blown version of Magics.  There are other file checking software packages sold and you can locate them by doing a search on the internet. 

Welcome to the Kaiser3D Rapid Prototype blog

Hi Folks and welcome to my first Kaiser3D rapid prototype blog entry.  I am Rob Kiser, the owner of Kaiser3D, a rapid prototype manufacturer based in Cedar Park, TX, just northwest of Austin.  I decided to begin a blog page in order to enhance information flow to users of the Objet PolyJet technology using knowledge gained as a former PolyJet 3D Printer Field/Applications Engineer.  We currently employ the Objet Polyjet rapid prototype 3D printer systems to produce rapid prototype models.  I started my business in January 2007 with one PolyJet Eden333 3D printer.  I quickly graduated to owning a second Eden333, then found myself needing the larger capacity and speed of the PolyJet Eden500V in order to meet my customer's increasing demand for high resolution rapid prototype models.   

I chose the Polyjet 3D printing system because of the system's high reliability factor, repeatability, ease of use, and high surface resolution.  As a former PolyJet and Selective Laser Sintering Field and Applications Engineer who serviced some very high caliber companies, I found these 4 items critical to a company's success in efficient product development goals.  Engineers and designers in the companies I serviced require a one-off rapid prototype that doesn't require reproduction due to a system malfunction, system calibration problem, or operator error.  These are reasons why it was critical to properly educate my users.  How does this help you?  We have the knowledge and experience at Kaiser3D to turn out a product that is most likely going to be the best PolyJet model you can expect.  

My experience with PolyJet 3D printer and Selective Laser Sintering systems, coupled with years of overall experience in many aspects of the Rapid Prototype industry, have led me to trust that these two technologies are the best the industry has to offer. 

I am very glad you have chosen to view my blog and expect to regularly see some very informative rapid prototyping information that I hope benefits you as users of PolyJet 3D printer technology.  Always feel free to add comments to my blog entries, let me know your experiences, and also know that no question is a dumb question.