1:500 3d-print

1:500 3d-Print

Scale: 1:500
Material: PLA
Machines: Prusa MK3
Software: Fusion360, Prusa Slicer

The Basic Design

One of the principal considerations in 3d-printing architectural models is how to efficiently cut them before slicing. The technique presented here is a simple way to improve speed and success rates while maintaining an acceptable level of detail. 

The principal idea is to separate the roof from the main body of the building so that the top acts as a lid. The body can then be hollow, consisting only of a wall, and prints drastically faster than a support-filled part.

Designing models for this sort of printing requires following some guidelines that have to do with the slicer and the diameter of the printer nozzle (typically 0.4mm).

PrusaSlicer gives us the following recommendation under the parameter “vertical shells”:

Recommended object thin wall thickness for layer height 0.20 and 2 lines: 0.86mm, 4 lines: 1.67mm, 6 lines 2.49mm, 8 lines 3.3mm…

The model below was designed following these rules. The outer wall of the building is 1.67mm thick, and the small lip at the top that houses the roof is 0.86mm. All vertical extrusions try to stay within a 0.2mm grid corresponding to the layer height specified for this print. A 0.2mm layer at the bottom of the print for the wall part was introduced to ensure adequate adhesion on the build plate.

The top part was printed conventionally with 20% infill.

The total print time for this model has been reduced by half by applying these simple techniques while drawing the model.

Material

Polylactic Acid (PLA) is a thermosoft plastic polymer material that becomes pliable or moldable at elevated temperatures. The temperature range for 3d-printing is between 200-230°C with a bed temperature of 60°C  to avoid warping. 

Results

1:500

1 to 500

1:500

Scale: 1:500
Material: PUR Block (Ureol)
Machines: Printer, Bandsaw, Thicknesser, Disc Sander
campus model

The Basic Design

1:500 competition models and especially additions to those models are a fairly common topic in architectural model building. Understanding the fundamental principles of planning for such a model brings you a long way and can help to convey your project in the proper context.

The white model is all about volumetric buildings and proportions. This model typology eliminates all other design aspects to give an “objectified” and comparable overview of a project. It is therefore imperative that details are reduced to only show the base volume of the building you want to build. 

The first step in making these models is to analyze your essential volume and subdivide it into different parts. In this step, we typically try to round dimensions up or down to the full – or if not otherwise possible – half a millimeter. This facilitates the actual building process and allows using materials with specific thicknesses. This additional planning goes a long way to making your model-building experience more efficient and pleasant.

 

Material

Various materials can be used to build 1:500 models, ranging from MDF and basswood to plaster or polystyrene. In our example, we used a type of PUR (Polyurethane) block material sold under many brand names worldwide (Ureol, Prolab, Raku-Tool, Renshape, …). Model builders choose the material because of its workability. It is easy to machine, sand, and glue and can take almost any finish. 

Raku-Tool has a density of 0.6g / cm3 and a shore hardness of 50-55. It can be used in the coated form as the final model or as the master for silicone forms. Joining two parts is quickly done with super glue, and gaps or imperfections can be filled with acrylic filler.

Technique

Building the model takes only a few simple steps that are repeated until all parts are finished and ready for assembly. We would like to point out that using the 3d-model to derive the surfaces and printing them as a template for producing parts is an essential technique that speeds up model-building and adds precision to your models. At this point, any preparation you’ve made during the modeling phase pays off its dividends. It typically shows in the details if the assembly logic of the model is simple and well understood. We hid some glue lines in the model by separating parts from the main body and covering the potential problem spots.
 
1. Create a simple 3d-model and subdivide it into parts 
2. Cut your material on the bandsaw roughly into the different thicknesses needed for your project
3. Plane the material to the precise dimensions
4. Mount the templates with spray adhesive to your stock
5. Cut your parts to size, leaving a margin of approximately 1mm
6. Finish your parts on the disc sander
7. Assemble your parts according to your 3d-model
! Sand parts and surfaces that are difficult to reach (inside corners) first!
8. Make sure to sand your whole model with 220 grit to remove all marks from the disc sander
9. Finish your model with primer and top coat

 

Adhesives

Adhesives For Model Building

This list explains some of the basic types of adhesives commonly used in model and prototype building and should serve as an overview to guide you in the right direction. Please do your research for specific application techniques and safety procedures for chemicals and adhesives before using them. Always work in well ventilated areas and wear your personal protective equipment if necessary.

 

More information on adhesives can be found on www.materialarchive.ch

PVA Glue

Polyvinyl Acetate Glue is typically sold as white glue and used on various materials – mostly paper and wood. Objects that must be joined permanently need clamping pressure to form an acceptable bond. PVA glue is stronger than wood, meaning that the material will fail before the glue does. The glue is excellent for gluing edges of the cardboard and is fast curing if applied in small amounts. Model builders typically apply PVA glue with a toothpick to the delicate edges of the card to avoid excess moisture and slow curing.

Materials: Wood, MDF, Paper, Cardboard, Leader, Foam Board

Further reading...

CA Glue 

Cyanoacrylate Glue is the go-to glue for professional model builders. It typically comes in three types of viscosities. Low viscosity for fixing cracks and applications that rely on capillary action. Medium viscosity for general purposes and low viscosity for applications where the glue needs to fill small gaps. CA glue can be used with a dedicated accelerator to speed up the curing process. For special purposes, the glue can be mixed with talcum powder to form a soft putty for filling and sanding or baking powder to instantly cure the glue and form a hard, durable joint.

Materials: MDF, Wood, PU Block, PS

Further reading...

Contact Adhesive

Contact Adhesives can join a wide variety of different materials. The process typically involves applying the glue to both sides of the joint, waiting for a couple of minutes for the glue to dry, and then pressing the two parts together. The glue is activated by pressure. This technique lends itself to applications where large surfaces must be laminated together and are not used in wood joinery or constructions where edges are joined. Typical applications are laminating some top layer to a substrate like in veneering or for joining foam.

Materials: Laminates, Foam

Further reading...

PU Glue

Polyurethane Glue is activated by moisture and tends, depending on the type of glue, to expand (foam). The foaming action helps with filling any voids in unregular surfaces and parts. Typical applications range from installing door frames to manufacturing plywood prototypes. PU Glue is a niche product in model building and is primarily used for laminated plywood or difficult glue-up situations. 

Materials: Wood, Plywood, Veneer

Further reading...

Dichloromethane

Dichloromethane is a clear, water-like, odorless solvent that can be used to join acrylic glass and polystyrene. It creates an almost clear joint by opening the chemical bond of the plastics to fuse them back together once the solvent is gone. Dichloromethane is extremely toxic and volatile. It should be used sparingly and with caution only in well-ventilated areas. Alternatives to Dichloromethane have specially formulated CA Glues for PMMA that have reduced off-gassing characteristics.

Materials: PMMA, PS

Further reading...

Epoxy

Two-component epoxy glues are in model building most commonly used in the form of 5min epoxies when dissimilar materials like wood and metal need to be joined somehow. Epoxy glues, in general, have a wide variety of applications ranging from boat building and the aviation industry back to the hobby market. Remember that epoxy produces an exothermal reaction during the curing process that can lead to extreme temperatures and even fire. Always mix small batches of epoxy (<100g) and spread excess glue on a flat surface for curing. 

Materials: Wood, Aluminium, Composites

Further reading...

Spray Adhesive

Spray Adhesives come in high strength and positional variants. In modelbuilding, the prepositional one is mainly used for gluing paper layouts to parts for cutting and sanding. The high strength or permanent type can be used to clad volumetric models with paper, veneer, or fabric.  Besides these two main ones, you can find an assortment of more specialized spray adhesives on the market, for example, for gluing polystyrene or foam.

Materials: Paper, Veneer, Fabric

Hot Glue

Generally speaking, hot glue has a bad reputation among model builders because of its strong association with bricolage. Nothing could be further from the truth – hot glue, applied properly, is fast and clean. Model builders use hot glue for all sorts of applications where water-tight joints must be created, like in mold building and in situations where you have to speed up an assembly process. For example, when you join wood, a drop of hot glue holds the parts together while the PVA glue dries. Not a method employed by fine furniture makers, but a valid way to get things done in the model shop.

Materials: Foamboard, Corrugated cardboard, PMMA, Leather

Further reading...

Silicone

Silicones are available in various formulations that highly depend on the use case. Silicone which is important as glue, comes in the form of caulking and is used in the building industry as an elastic sealant for different materials. In the model building shop, silicone adhesive is used for mold making and joining glass and mirrors. Ensure that the parts that need to be joined are grease-free before applying any silicone and allow for drying overnight for best results.

Materials: Glass, Mirrors

Further reading…

Construction Adhesive

Construction adhesive as a very high initial tack that eliminates the need for clamping, making it ideal to fix something to a wall or a ceiling without any extra work. In the model shop construction adhesive is mostly used to join concrete parts or to mount an exhibition piece to a wall.

Materials: Concrete, Plaster Board, Wood

Double-Sided Tape

Double-sided tapes have become more and more capable in the last couple of years. They are useful for provisionally attaching facades or other parts to a model and permanently joining parts. Being on the lookout for new applications and types of double-sided tapes is always a good idea. The vastness of different types of tape for different applications demands a good technical understanding to find the right tape for any application. In the model shop, the simple double-sided tape used for carpets is the most versatile one and is frequently used to hold parts on jigs for sanding and gluing down sheet stock to different substrates. 

Materials: various

Extrusion

Plaster Extrusions

Scale: Free
Material: Plaster, PMMA, Wood, Shellac

The Basic Design

For this tutorial, a simple profile was chosen as the basis for creating a plaster extrusion that gets assembled into a ring of eight segments. 

Having methods and techniques at hand that allow the creation of complex objects is of great importance in model building. It allows the designer to think in different materials and lets him or her express form in a more precise way.

Keep in mind that you will benefit the most from working with this material if you apply your twists and variations to it and do not just follow the examples.

Material

Plaster, properly understood, can be used in different stages of its hardening process. The most common way of working with plaster is, of course, pouring, but carving, sculpting, extruding, and even turning is possible. 
The extrusion process takes advantage of the fact that plaster has a gentle curing curve. Freshly mixed, it is too liquid to be of use for extruding the material, and a bit of patience is needed to get to the right consistency where the plaster is almost like cream cheese. In this phase, plaster builds up quickly and can be extruded into nearly any shape.   
 
Further reading: Plaster basics

Technique – Extruding Plaster

A simple plaster jack can be built with wood and laser-cut acrylic.

Prepare the plaster for your profile in multiple buckets to always have the right consistency at hand.

Building up the first part that will become the mold for the profile.

Applying shellac as separating agent before the changing the template.

Building up the profile with the profile template. This can be done without the jack for short sections 

Clean the plaster jack / template frequently for best results.

The final pass uses a relatively liquid plaster that fills in the last little voids.

After 20-30min the profile can be carefully separated from the base.

Plaster can be cut with a dedicated bandsaw.

The parts can be glued with super glue after applying shellac to the surfaces that need to be joint together.

Lightly press the assembly with the help of some painters tape for 10-15min to allow for the hardening of the glue.

Examples

Safety Introduction

Raplab Safety Introduction

The Raplab Safety Introduction is the first introduction to the Raplab, its team, the workshops, general safety considerations, and working guidelines. It is a required course for everyone who wants to use our facilities – new bachelor students, exchange students, PhDs, MAS students, or no D-ARCH members.

The completed course grants you the right to get a Raplab-Account and lets you enlist for advanced classes that give you access to the wood, plaster, or digital workshop of the Raplab. This course by itself is only covering the safety foundation, and it does not grant you access to any of our workshops!

Follow this link to the moodle course: Raplab Workshop and Safety Introduction