The LittleRP was created to be a standardized and affordable open solution for resin printing. FFF printers like the Darwin, Mendel, and Prusa significantly lowered the barriers to entry for makers looking to get into 3D printing. The LittleRP aims to offer similar benefits by providing an easily self-sourced / expandable resin printer to the emerging resin printer community.
At the conclusion of the Kickstarter campaign LittleRP.com will become a primary source for those who would rather purchase an already sourced, high quality, well documented kit.
From the beginning the LittleRP was designed to be as simple as possible while still maintaining excellent print quality. By focusing cost constraints on the components that most directly impacted printing quality we were able to create a kit that has high accuracy, performance and detail while keeping costs low.
Our mission is to bring highly detailed resin printing to the makers, model builders, and jewelers for whom current offerings do not meet affordability, simplicity, or accuracy needs.
What is Resin Printing?
"Resin printing" (also known as 3D stereolithography) is a printing process which uses a liquid light-sensitive resin and a high intensity light source to build a 3-dimensional part, layer by layer. It is different from traditional FFF-technology that most are familiar with as instead of extruding hot filament in a linear pattern, the liquid resin is turned into a solid using light, with layers completed at much faster rates. Light sources used for this type of printing are typically a +2000 lumen DLP projector or a near-UV laser and subsequently yield parts with much higher quality and detail than is possible with FFF technology.
(ABOVE: Even at an identical .1mm layer height, resin printing is capable of superior detail and accuracy reproduction [Marvin Keychain by 3D Hubs / Thing:215703 )
The simple design of the LittleRP doesn't tell the full story of its development. Designed over several months and iterations the LittleRP has evolved from a one off fully printed machine to a production friendly printer of refined design.
The three fundamentals of the LittleRP
Affordability - While currently there is an influx of resin printers becoming available on the market there still remain relatively few inexpensive options. The LittleRP was specifically designed to be both affordable to acquire, and inexpensive to operate. By focusing on smaller higher detailed prints, we were able to shrink and simplify the resin vat design, which dramatically decreased replacement vat, re-coat, and resin costs.
Replacement vats are normally a costly item, with the LittleRP our replacement vats will be offered for a fraction of the price of other printers. The non-stick coating of the LittleRP resin vats only requires $1 of material to re-coat compared to $8-10 for larger printers. Lastly our build plates have been designed to be strong, easy to swap, and to use inexpensive aluminum extrusions.
Flexibility - The LittleRP is unique among resin printers in that it was designed to encourage 3rd party vat designs, linear motion components, and DLP light sources.
If availability issues arise or extra performance is desired, the LittleRP design is meant to be flexible to fit a variety of needs. For example, the linear rail can be swapped out for OpenBuilds V-Slot parts, the projector for different or higher resolution models, and a variety of stepper / leadscrew / leadscrew nut options can also be used.
Openness - At the Kickstarter conclusion the design files for the LittleRP will be made available on GitHub, this means you will have access to every STL, every measurement, every lasercut file, as well as BOM and build documentation. Do you want to modify the design? Does your makerspace want to do a self-sourced group build? We are happy to help you with any questions you may have.
Our philosophy with resins is to test as many 3rd party resins as possible and make recommendations based on price and performance. Our open stance means that you won’t be locked into costly proprietary resins.
Tested Resin Choices
Below are two resin options that have been thoroughly tested and recommended for the LittleRP printer. Most UV curing resins compatible with DLP based resin printers are likely to work with the LittleRP. One of the goals of the LittleRP campaign is to test new resin options as they become available and encourage further resin development.
MadeSolid Resins - MadeSolid's Deep Red formulation is an excellent choice for those looking for an easy to use consistent resin with minimal shrink, retaining accuracy with both large and small models. Because MadeSolid Deep Red shows less layer blending it appears best at 50micron layer heights as it better matches the XY resolution. MadeSolid Deep Red requires longer to fully clean from vats and build plates and is only available in the Deep Red color.
Price: $59 / 500ml - $99 / 1000ml
(ABOVE: 3D KitBash Skull [MadeSolid Resin])
(ABOVE: Super Hero Head by Terry Nghe [MadeSolid Resin])
(ABOVE: Open Source Hardware Ring by DjSplitterPro / Thing:358031 [MadeSolid Resin])
MakerJuice Resins - MakerJuice SubSF for LittleRP resins are vibrantly colored and tailored for use with the LittleRP. MakerJuice SubSF for LittleRP is available in a variety of colors and is ideal for 50-100micron layer heights where both detail and layer blending are desired. MakerJuice SubSF for LittleRP is easy to modify for specific printing needs due to it's easy color mixing and availability of raw pigments. Mixing pigments allows for custom colors and for tuning to 25-50micron layer heights.
'SF' stands for snap fit and is suitable for items that require or benefit from some flexibility. MakerJuice SubSF for LittleRP exhibits some shrink and will benefit from hollowing of more solid models before printing. MakerJuice SubSF for LittleRP is also a very easy to clean from vats and build plates. The Deep Red coloration is recommend for the finest of detail work as it is the best at blocking UV.
Price: $32 / 500ml - $57 / 1000ml
(ABOVE: Doge Rocket by esprite / Thing:325098, Marvin by 3DHubs / Thing:215703 [MakerJuice Resin] Condor Head and Doge Rocket models were hollowed)
(ABOVE: Bubble Ring by mmba / Thing:1308, Split Ring by CAVA Studio [MakerJuice Resin])
(ABOVE: Drone Gear by ajolivette / Thing:21342, Gear Set by badBrick / Thing:146289 [MakerJuice Resin])
(ABOVE: Bubble Ring by mmba / Thing:1308, Marvin by 3DHubs / Thing:215703, Open Source Hardware Ring by DjSplitterPro / Thing:358031 [MakerJuice Resin])
What is included in the kit
The Kickstarter kit comes in Complete, Complete HD, Projectorless, and Projectorless Without Printed Parts options. The Complete kit includes everything you need to get printing, whereas the Projectorless option requires you to supply your own DLP projector. The recommended choices and options for a projector can be found in the “Projector Options” section further down.
Projectorless kits are available for worldwide shipping, due to different countries power requirements, regulations as well as the fragility of projector bulbs, we are not offering complete kits outside of the US at this time.
Projectorless Without Printed Parts means that the kit does not include the red FFF printed PLA pieces in the photo above. This option is for those who already have an FFF printer and wish to print these parts themselves and obtain a kit for a cheaper price. PLA or PET are recommended as ABS will soften with resin contact.
The kit does not require soldering, and can be fully assembled using metric allen keys and open ended wrenches. The electronics and build plate come fully assembled.
- Lasercut Acrylic UV Shield Panels
- Lasercut Melamine Bonded MDF Panels
- Lasercut Shutter
- 2020 T-Slot Frame Material
- Printed PLA Parts
- All Required Fasteners
- Modification Spacers for projector
- Pre-Assembled Build Plate and Knob
- Circular Pre-Coated Vat (4" OD 3.75" ID)
- First Surface Mirror
- HiWin Linear Rail
- Sparkfun Redboard pre-loaded with GRBL firmware
- Custom LittleRP Arduino Shield w/ Stepper Driver
- High Quality DC Power Supply
- Integrated Leadscrew Stepper and Nut
- 100ml of your choice of MadeSolid Deep Red Resin or MakerJuice SubSF Resin in your choice of Red, Yellow, Orange, or Green
Modified 1024x768 DLP Projector (Complete Kit Only)
- 1920x1080 DLP Projector (Complete HD Kit Only)
You will be able to add additional vats, non-stick coating supplies, and resin to your order before it ships.
- Stepper resolution of .005mm ( .020mm prints have been tested)
- 25/50/100micron recommended layer heights
- 60micron x/y resolution with Acer x1240
- 40micron x/y resolution with Acer P1500
- 60x40x100mm available build area (Acer x1240 / Acer P1283)
72x40x100mm available build area (Acer P1500) build area does not equal maximum printable size please see "Print Constraints" below.
- Tested with MakerJuice and MadeSolid resins
- Ideal layer times 1000ms-5000ms
Slicer / Controller - The software we are using to slice STL models and feed them to the LittleRP is called Creation Workshop and is developed by Envision Labs ( http://www.envisionlabs.net/ ). The Creation workshop package is designed to work with Windows, Linux, and Mac computers. We encourage you to download the software and make sure it runs on your computer before deciding to back the LIttleRP campaign.
The LittleRP acts like a secondary monitor, with the Creation Workshop software managing what the projector displays as well as sending movement commands to the LittleRP.
(ABOVE: Creation Workshop Layout View)
(ABOVE: Creation Workshop Slicing Settings)
(ABOVE: Creation Workshop Slice View)
Hollowing Software - There are a variety of free software packages you can use to hollow models and to add structures. While resin printers can handle much more extreme overhangs than FFF printers, supports are still required. Autodesk® Meshmixer® is a great general purpose model editing program that offers hollowing features.
Hollowing your models has a number of benefits, firstly you will be able to print larger models if they are hollowed as it reduces the area of cured resin that comes in contact with the non-stick coating. Hollowed models will also extend your non-stick coating lifespan as solid models can create extra heat and impart more stress onto the coating. Small models such as jewelry typically do not require hollowing as the average surface area in a slice is already low.
(ABOVE: Hollowed models with holes to release uncured resin)
Support Generating Software - Adding extra support structures to a model before printing can be necessary. In cases where a part needs to be rotated in the x or y axis, elevated off of the build platform, or has extreme or negative overhangs supports may be needed for the part to print successfully. Creation Workshop, Autodesk® Meshmixer®, and B9Creator® Layout software are all excellent options that are free to use. Each generates different types of support structures, so becoming familiar with each is highly recommended.
"B9Creator" is a registered trademark of B9Creations, LLC in the United States. B9Creator’s Software is open source, licensed under the GNU General Public License, version 3.
For the purposes of our kit, we recommend supporters choose either the Acer x1240, Acer P1283 or Acer P1500 projectors. The LittleRP is designed to be flexible with the projectors it supports, the three Acer options are simply choices we have verified to work with the design and have created mounting solutions for. When the campaign becomes successful we will make it a priority to offer additional projector recommendations and provide the necessary modification / mounting information for them.
All prints shown have been printed on a 1024x768 projector
1) The Acer x1240 is an inexpensive (~$315+ USD) 1024x768 projector that will require user modification to work with the LittleRP. A modification guide and video will be available and consists of opening the projector to insert 3 spacers into the lens housing. It is also possible to use the Acer x1240 with external close-up filters if you are unable or unwilling to modify the projector internally.
2) The Acer P1283 is the replacement for the x1240 described above. Like the x1240 it can either be modified internally, or used with close-up filters.
3) The Acer P1500 is a more expensive (~$600+ USD) 1920x1080 option but one that requires no modifications to work with the LittleRP. At very close distances the P1500 does exhibit a sweet spot in the center of the projected image and may exhibit some softness towards the edges.
4) For the more technical of supporters the re-use of new and used DLP projectors is possible. Our first LittleRP utilized a $99 used Dell projector. We will provide basic instructions on what to look for in a DLP and how to adapt it to the LittleRP.
Design choices have allowed the LittleRP to maintain a high print quality while maintaining a low cost. Finely detailed items such as jewelry can be printed on the LittleRP thanks to its rigid design and high quality linear motion components. As can be viewed in the close ups below a high degree of accuracy and detail can be achieved.
(ABOVE: Tudor Rose by loubie / Thing:408189 [MadeSolid Resin])
(ABOVE: At 25 Micron layer height you can still read "Make:" on the back of the smallest robot)
In the most basic configuration there are some printing constraints to consider. Because the basic version of the LittleRP does not use a method to peel the print from the vat surface you will need to be mindful of the volume your print requires. The basic version of the LittleRP is intended for jewelry, miniature figures and similar styles of prints. Larger models can be printed successfully by first hollowing and venting the STL files, guides on how to do this will be provided.
Resin printers require trial and error as print failures will naturally occur. Like FFF printing, you may need to angle a part differently, add supports, or change curing time in order to achieve satisfactory print quality. Ultimately some models may not be printable due to a variety of factors.
The non-stick vat surface has a limited lifespan but is replaceable. You can expect to achieve between 10-15 smaller sized prints in any one location on the vat before needing to replace the vat surface. By printing models on different parts of the vat, or hollowing your models you can increase this number.
The non-stick coating we recommend is Sylgard 184 or comparable such as the MLSolar product shown below. To replace the vat surface you first simply peel up a corner of the damage surface and remote it completely. The surface is a cured silicone product and is very rubbery and easy to remove.
Mix your Sylgard 184 according to direction then pour 10ml (approximately $1) into the empty vat lying on a level surface. The non-stick coating will set in as soon as 4 hours and will be fully cured in 48. We recommend having extra vats and non-stick coating on hand so that you can continue to print uninterrupted. Extra vats and non-stick coating will be available to add to your order when we collect your shipping costs.
(ABOVE: Removed damaged non-stick coating (left), Vat with new non-stick coating (right))
Kickstarter allows LittleRP to accomplish several key goals:
Volume Discounts - Although an important part of the LittleRP design is that it can be self-sourced in single quantities there are many benefits to volume purchasing. Volume purchasing will allow us to provide a more cost effective kit, as well as offer lower pricing on linear motion components to self-sourcers compared to what they could achieve sourcing on their own.
Creation of a User Community - We have teamed up with buildyourownsla.com to provide a support forum for LittleRP users. By having an initial group of LittleRP users we can seed the forums and get a jump start on creating a prosperous resin printer community. The buildyourownsla.com forum also attracts many additional hobbyist and professionals. These users will provide another layer of support and resources for those looking at extending the capabilities of their LittleRP or other printer offerings.
Investments in Manufacturing Options - The successful Kickstarter campaign will allow us to make an investment in casting, lasercutting, and milling equipment. Having these technologies in house will allow us to test modifications and offer new features at a much faster rate. The LittleRP is the first step in a line of quality printers we hope to offer, having additional manufacturing options will substantially increase the speed we can make this happen.
Standalone Host - Currently most DLP based resin printers need to be attached to a personal computer while they are printing, the printer acting as a secondary monitor. With the success of the LittleRP Kickstarter we will actively pursue the development of a Raspberry Pi, BeagleBoard or similar host. Such a host will be capable of controlling both the printer as well as the DLP projector freeing up your personal computer during printing. Once developed the standalone host will be available for anyone to use, not just LittleRP owners.
Projector Testing - A barrier to DIY DLP resin printers is selecting an appropriate DLP projector. With the funds raised we can purchase additional projector models and test them for suitability with both the LittleRP as well as DIY DLP printers. Projectors found to be suitable will have mounting solutions documented and available for download.
Resin Testing - There are a number new resins reaching the market with properties that make them suitable for casting, flexibility needs, and biocompatible applications. With a successful Kickstarter campaign we will have the ability to purchase additional resins for testing and provide configurations for their use with LittleRP.
One goal of the Kickstarter campaign is to provide capital for testing modifications of the original design. We are currently in development of a tilting vat upgrade, and feel it offers a unique solution to peeling cured layers. In the video below you can see the rear of the vat and the build plate raise in unison. Both the vat and build plate travel can be controlled independently and by adjusting the ratio of the two you can move the fulcrum point of the peeling motion.
A tilting vat allows you to print larger or more solid models and print them with a larger variety of resins. A tilting vat substantially reduces the limitations that are created by the sticking and suction forces common with bottom up resin printing. A tilting vat will not increase the available build area, rather allow you to fill more of the build area with cured resin.
(ABOVE: LittleRP using Tilt Printing Solid Huntress Bust by Yan / Fantasygraph [MadeSolid Resin])
(ABOVE: LittleRP using Tilt Timelapse - Doge Rocket by esprite / Thing:325098 [MakerJuice Resin])
(ABOVE: LittleRP using Tilt Timelapse - California Condor Head [MakerJuice Resin])
(ABOVE: LittleRP using Tilt Print - Brian Bust by Michael Balzer of slo3dcreators.com [MadeSolid Resin])
The current state of LittleRP
The LittleRP has already been produced in limited quantity for beta participants. There are no design hurdles to solve, no further testing that needs to be done, the design is proven and ready for production at the conclusion of the Kickstarter campaign.
After Kickstarter Ends (Shipping / Projector / Resin)
Before rewards ship we will contact you to obtain information needed to tailor your kit based on your preferences. During this time you will also be able to add additional vat, non-stick coating supplies, and additional resin to your order.
We will ask which projector you intend to use and include a base plate and hardware specific to it.
Shipping costs will also be finalized and collected as part of this procedure. We expect domestic unassembled projectorless kits to fit inside a USPS Priority Mail Large Flat-Rate box for a shipping cost of $20 (assembled and kits with a projector will incur additional shipping charges). The flat nature of the kit parts lends themselves well to efficient packing and we will make every effort to work with our international buyers to keep shipping costs low.
Kickstarter Campaign (0-30 Days)
- Provide casting updates
- Host Dropcam live print sessions
- Start printing PLA parts
Campaign Close (30-60 Days)
- Allow for delays in fund transfers
- Purchasing controller components
- Finalize frame design
- Finalize shipping and packaging options
Bulk Order Phase / Pre-Assembly (60-90 Days)
- Place bulk component orders
- Start Pre-Assembly of Controller
- Start Pre-Assembly of Build Plates
Pre-Assembly / Packaging (90-120 Days)
- Collect shipping costs based on location
- Modify projectors
- Package kits
Campaign Completion (Day 120)
- Rewards Ship
Special Handling for Resin Printers
UV curable resins have a special set of handling requirements that should be understood before one starts printing. Uncured resin should not be allowed direct contact with skin as repeated exposure can cause skin sensitivity similar to a rash / allergic reaction. Once properly washed and cured, printed parts are mostly inert but should not be used where they will have prolonged skin or any food contact.
It is important to have a non-porous or covered work surface dedicated for your resin printer as spills and splatters will and do occur. In addition protective eyewear and gloves should be used at all time when handling uncured resin.
LittleRP has made a strong effort to form and support domestic partnerships whenever possible, below are a list of companies that your Kickstarter reward will help support in addition to LittleRP:
100 Units - Metal build plate arm and mirror holder.
We will make every attempt to include the stretch goals once reached but they are not guaranteed. Once a goal has been reached a new higher unit goal will be added.
Risks and challenges
Risk associated with the LittleRP is low as development of the product has already completed and no special tooling is required.
Because we wanted to make the LittleRP as maker friendly as possible there is a reliance on FFF printed parts in the design. Depending on the success of the Kickstarter providing these in high enough volume may prove challenging. Our initial plan is to scale our existing print farm to meet this demand. If Kickstarter demand becomes something that is not feasable to meet with our FFF printers we will switch certain printed parts (Arm / Mirror Holder) to folded metal sheet. The metal parts will be backwards compatible with the FFF printed parts, but allow us to scale the kit to larger quantities more rapidly. We already have the sheet metal parts designed and have received manufacturing quotes.
With any project there may be unforeseen difficulties and delays. In such a case we ask that you be patient while will make every effort to minimize potential impact.Learn about accountability on Kickstarter
- (30 days)