Thank you all for participating.
We finalized the purchase of our machine a month ago. I will outline our experience so that other people in the same situation in the future might benefit from it. I apologize in advance for the length of this post.
It become clear that just but having the OEMs printing me parts and me evaluating them would not work. I felt the need to run the machines ourselves and I am glad I did.
I ended up requesting a 2 month rental (with a purchase option) from each company, something, I was told, that had not been done before;
- The Dimension people pondered on the idea came through with a proposal in a few days. Within a few days, after approval of their proposal, they installed the 3D printer and the Cleanstation for removal of the support material.
- The InVision people were much slower to make up their minds. Eventually they did rent me the oven, but not the actual 3D printer, and offered running parts for me at a very competitive rate. By the time that happened however, I had already been running the Dimension for 4-5 weeks and made dozens of parts with it.
The parts we make are not very big, say 200mm x 50mm or so, but most of them have a curved back.
We run into problems with the InVision pretty quickly. It became apparent the parts curvature did not match that of the math data files, but rather the curvature of whatever surface the part was laid on to cool off. We probably could have overcome that problem by first making a “support” model of a block with a face of the curvature the part was supposed to have, then making the part model and finally laying it to cool off on that “support” model so it would harden to the proper curvature. We never tried it though, too much screwing around and too much wasted material.
The parts match the geometry perfectly. The removal of the support material has not affected the shape of the part. As an added bonus, if a part is flat the support material can be taken off by hand in seconds, so you don’t even need the Cleanstation.
Shortly after starting the tryout of the machine, it broke down and it took almost two weeks to start getting parts again.
We have gone through 10 cartridges of material already and it has not had a problem yet.
SUPPORT MATERIAL REMOVAL
The wax melts in the oven, simple enough. The problem is that it is a somewhat messy process, you do end up with wax in you hands (similar to getting hot wax from a candle) and it might be time consuming to take it off. You want to dedicate an area to do this removal process.
On small detailed areas, we found it almost impossible to get rid of 100% of the wax support material. This might create a problem with post processing. Without the post processing, the wax visually detriments from the part as it is of a more whitish color than the model material and it stands out. With time and hobby tools, you can get 99% out, but it is annoying.
The support material can be thrown with the regular waste once it is solidified.
Drop the parts in the tank, come back in a couple hours and remove parts from tank. Shake off excess, let air dry and you are done. It is seriously simple and hands off, we love it.
For us the solution on the Cleanstation tank can not be sewered (PH is 11.0 or above). We have to treat it as corrosive, hazardous waste and make proper arrangements for its disposal. Again for us that is not a problem as we have the facilities to treat it internally . To some other companies, depending on their status with the EPA, they might be able to just dump it in the sewer without a second thought. Check with your local EPA to be safe and plan accordingly.
Layer build thickness is about .0015". The part’s finish and resolution is fantastic. You can really capture most details that are at least .015"-.020". Unfortunately, the material used is translucent an if you have features on front and back of the part it is annoying to have them so visible when evaluating the model. A coat or two of primer would take care of that if you have the time to go through prepping and painting the part.
The material drills, sands and taps very nicely. Painting with a paint that requires oven curing time will affect your part curvature, if it has any.
Their layer build thickness is .010" so any features smaller that about .030" might not come out right. You have to consider model placement on the machine taking into account the layered build process. It will affect the look of your part if it has any type of curvature. Additionally you need to consider the direction of the “grain” when making a 3D printed part if you will be applying any force to it. For most of what we do, the parts are good enough.
The material drills and taps very nicely. Painting will require some serious amount of prep work. You can’t just throw paint as it is a porous material. You will have to sand, apply a filler and then paint. I am sure with time you can get very nice looking parts, but don’t be thinking it will be a 5 minute operation. Then again the porosity of the material is really nice for vacu-forming.
PART DIMENSIONAL STABILITY
Part dimensional stability was somewhat of a hit and miss. Sometimes they were OK on the XZ and not on the Y, other times XYZ were good, and other times, none were good. Not sure why, but I suspect the post processing of the parts to be the main reason.
Dimensionally the parts come pretty much right on the money, but you again have to keep in mind the layered build process and positioning of the model during the build.
Prior to doing this rental period, we were leaning towards the InVision as the parts finish was so good. Shortly after starting the rental (try-out) period, it became clear the Dimension was what we rather have, and that is what we purchased.
Other that the great detailed finish you get on the InVision, we had many more areas of concern with all the other aspects, including reliability. Though I requested references 3 times, the InVision people only came up with one name. When I talked to this person, he was in marketing and could care less if the model was half inch bigger or smaller than the real part as he was just showing a concept. The Dimension people gave me 5 references, 3 of them local, and all in the engineering side, which is what we were looking for. They all had pretty much the same experience with the Dimension as I stated above. Most had had the machines for over 12 months and some were ordering a second machine.
The dimension part finish is not great, but it is not bad. We do not bother trying to make it look smooth and glossy as the raw parts convey what we are trying to do. Most of the times, we just bolt them on the machines they are going into and go at it. They might not be pretty, but they work and that is what counts.
In sort, after three months with it, the Dimension proved to be all that you have read about and all that you have heard from their reps;
- it runs, non-stop and without trouble
- parts are consistently dimensionally correct
- material comes in different colors, which is nice if you have a part made up of different components. Material is very easy to change.
- it allows you to think of the part you are designing and to keep on working. You feel 100% confident once you hit print, you can keep working on your design and don’t worry that the Dimension might stop, screw up , etc. It just works !
- support removal is mindless and effortless
Hopefully this helps the next person making the same decision.
Let me know if you have any questions.