Smoothness of SLA Parts

Hi,

CAn SLA make parts that are smooth like a plastic lens?
I se parts that are stepped or kind of rough but others say they are capable of smooth surfaces and some claim to be able to make prototype lenses.

Anyone expert in this can tell me about what they can do nowadays?

Yes you can use SLA to do clear lenses. It all depends on the types of resins the manufacturer uses.
The SLA’s that you see with ridges on them are unfinished, which means they have not been “polished”.

OBJET or MultiJet (BOJ and MJM) usualy give better finishes since the layers are finer. you’d still need polishing though.

have you thought about machinning? the resolutions there can be very high to get very good finish.

OBJET or MultiJet (BOJ and MJM) usualy give better finishes since the layers are finer. you’d still need polishing though.

have you thought about machinning? the resolutions there can be very high to get very good finish.


What, Have you even had an sl made in the last 5 years. viper machine has .002 layer thickness.

Yes SLs can be made smooth infact perfectly clear with pollishing. I have had actual lenses ran. The main issue is the resolution of your STL file, never use the default settings from pro or SWXs. always set the tollerance to the lowest allowable setting. In SWX slide the slider to the extream right, on Pro enter 0 and it will automatically give you the lowest possible. also set the angle deviance to 10 deg. This will make a larger file, however it will build the best models.

In my recently past job I ran the design department, as well as the RP sourcing department of a small LLC. Over 6,000 prototypes mostly sla, sls, and rtv in the past 2 yrs. Though objet is getting better every month…it does not compare to a quality SLA vendors models.

O-Yeah, and the lowest priced SL providers are generally using 5+ yr old machines, low quality resin, and running the machines on the lowest possible resolution to cut machine time. From my experiance you get what you pay for when it comes to sla builds.

Give me some details on what you are hoping to accomplish with your prototype, and I will help you choose the right resin and machine. Then you simply need to find a reputiple vendor. I find that the best ones are in Chicago, Indianapolis, and California. Pretty much in that order.

Quadra Tempo Objet resolution in DPI (600x 300y 1270z)…
1inch/1270dpi = .000787as a thickness of a layer.
I am by no means an expert, but I have done a lot of research on RP technology last couple of years.
And have seen, oredered, touched a number of prototypes in different materials, from different processes.
Just offering my experience.

resolution limits for topographic part building is about .002" step. if you need a polished finish, you will need to hand sand and buff. Even machining won’t get you a polished finish.

What’s the best way to get SLA’s smooth? Prime them and then sand with various grits of sandpaper? What grit should I start with?

use a buffer wheel.

anybody know what the output smoothness of the z corp. z810 is like ? i expect that since it prints in colour, there really should be no sanding required…anybody know of any other similar 3d colour printers ? that alcohol in the rp room and fumes in the paint room are starting to get to me