Guide to  3D printing

Guide to
3D printing

What is 3D Printing?

3D Printing is used to construct simple and complex geometrics by fusing together very fine layers of powder, liquid or a continuous filament. The process starts with a CAD model sliced into cross-sections. Each cross section is mapped onto the surface of the rapid prototyping material which is fused or cured to the layer below. High tolerances of the 3D Printing process mean that it is ideal for producing fit-form prototypes that are used to test products before committing them to a chosen method of production. Our Viper SLA system produces the highest surface finish and dimensional accuracy of all rapid prototyping methods.

What's the difference between SLA, SLS and FDM?

SLA (Stereolithography)

• Computer controlled laser builds structure from a liquid photopolymer that solidifies.

• Parts produced with high accuracy and excellent surface finish.

SLS (Selective Laser Sintering)

• Computer controlled laser heats and fuses together a powdered material.

• Low cost and low quality.

FDM (Fused Deposition Modeling)

• Material is heated and then in controlled quantities deposited in layers.

• Slight seam shown between layers.

Can you 3D Print without a CAD file?

No, but don’t worry, we offer full 3D parametric CAD data creation. Contact us for more information.

Why do I need to produce a STL file?

STL is the industry standard file format for 3d printing machines. It converts parametric CAD data into surfaces constructed of triangles that is then sliced by the printing software into the build layers. There are various free STL converters available on-line. Be aware though that, if you’re struggling to convert your data, it can be a good indicator that your CAD data is unsuitable (poorly stitched surfaces etc).

What are the design rules for parts built as SLAs?

• As an additive process, the greatest cost lies in the volume of material in the part. Always minimise wall thickness and solid sections as much as you can.

• Some CAD data (such as library CAD for gaming etc.) comprises a skin with no actual thickness. This will give you a falsely low material volume calculation and an incorrect estimate or quote.

• If you create enclosed box sections, you must create drain holes (min dia 5mm) to allow the uncured resin to be drained out.

• Some enclosed box sections might retain build structure. If this must be removed then we require sufficient access to enable us to remove the structure with tweezers.

• SLA resin is hygroscopic. If your parts will be in contact with fluids or used in a humid environment, please contact us for advice on sealing the surfaces of the SLA.

• Please ensure your parts can fit in the build envelope available (see question 7 for extents). We cannot cut up STL data.

Why does part orientation matter?

IDC will re-orientate your part to achieve the best quality build. However you may have certain features that are more important to you. Please assign x, y and z values to best fit your preferred orientation and detail your requirements in the naming field of each parts. To help you here are some pointers:

• If you have features that need to be truly circular, we will need to orientate these so that the circle is lying flat when viewed in plan view. If you have circular features in various axis then let us know which is the most important and we will orientate the part accordingly.

• The surface facing downwards will have the latticework build structure attached. IDC undertakes basic removal of this within the cost but does not clean the parts up beyond this within the on-line quoted cost. Please indicate is surface finish is more important on one face than another.

• Surfaces at a shallow angle to the horizontal may well show ‘stair-stepping’ more so than more vertical surfaces. These can take more post-finishing to remove.

If we receive no specific instructions, we will use our experience to best fit the parts to produce the best results. We can undertake more extensive post-finishing and spraying etc at additional cost. Please contact us directly if you have requirements beyond 3D printing.

Do I choose normal or high resolution?

• Normal resolution has a build envelope of 250 x 250 x 250 and is accurate to 0.1 mm

• High resolution has a build envelope of 125 x 125 x 125 and is accurate to 0.05 mm.

A part built in high resolution is always more expensive than a part built in normal resolution. To get comparative prices enter both options in our on-line quoting or estimating systems.

What are the material properties of SLA resin?

How do I use the online quoting system?

• For quotes and automatic ordering please use the upload STL files tab.

• If you do not have STL data but want an idea of the cost of having an SLA built then use the enter part dimensions tab

• You can add as many parts as you like and pay for this online or receive a formal PDF quote via email, instantly.

What will I be getting for my money?

Our on-line service includes the following:

• Best orientation of your STL files onto the build platform. Parts must be provided to us sized to fit within the build platform and to a print ready quality.

• Removal of build structure from the part

• UV curing of the part

• Packaging and despatch

Not included but available as services we can provide at additional cost are the following:

• CAD data creation and manipulation. We can create parts from scratch or manipulate parametric CAD data and convert to STL format for you. Please note that we cannot modify or alter STL data.

Note that IDC has a full product design, engineering, modelmaking and prototyping capability.You may assume that a 3D print is what you need. If you are not sure then feel please contact us for advice on the most appropriate solutions to your requirements.

Is delivery included?

There is a charge for delivery, as outlined in your quote.

International clients should contact us directly for courier costs and for quotes without VAT added.

What about data protection?

IDC takes client confidentiality very seriously. Until you place an order, we cannot see your data. We retain your data for a period of 30 days after despatch of your parts and then it is deleted from our systems.

We cannot offer to sign individual NDA’s for parts ordered through our on-line system though we are happy to do so at additional cost. Please see our Terms & Conditions for full details of our data protection policy.