Revised_statement_of_Work.pdf

STATEMENT OF WORK

1. Objective/Requirements

NASA LaRC is in need of one (1) custom-built electrically heated 56.5’ long batch curing oven and associated control system to process up to 54.5’ long slender composite structures. Also of a similar length stand with swivel casters (rolling loading cart) with a top work tray to be used as a flat surface to lay the part molds on top.

2. Characteristics, Scope, and Specs

NASA LaRC requires to purchase a custom-built convection curing oven with the following specifications:

1. GENERAL SPECIFICATIONS

Process: Cure vacuum bagged molded parts for aerospace applications.

Product Dimensions: Current carbon foam molds are approximately 54.5’ in length x 1’ x 1’.

Product Weight: Weight for two molds to be cured side by side up to 6000 lbs.

Part Loading/Unloading: Part loading will occur through the front door of the oven once the rolling cart is axially aligned with the oven longitudinal axis. Unloading will follow a similar operation. The oven shall include internal elements and features (wheels, V-groove inverted angle tracks) for correct alignment of the rolling cart axis with the oven axis for ease of manually loading the work tray with the molds and parts.

Temperature: Maximum temperature rating of up to 500° F. Normal operation is at 350° F with the possibility of reaching 450° F to run free-standing post-curing cycles.

Temperature Uniformity: Required Accuracy and uniformity across the heat chamber of ± 10° F (± 5° F optimal) at any given temperature up to 450° F. Specify what range could be guaranteed assuming the use of carbon foam (CFOAM) molds to cure thin composite parts. In addition, specify what type of test/s would be done at the vendor facility to determine the temperature uniformity with a surrogate material or an empty chamber. Such tests are required and the delivery to NASA of the test results could be used as a milestone in the payment planned proposed.

Cure cycle: The design capacity of the equipment, when heated from ambient, needs to have sufficient capability to heat 1,500 pounds of carbon foam (CFOAM) tooling or 6,000 pounds of aluminum/stainless steel tooling plus the work tray material following this cure cycle: ramp up from 70° F to 350° F in approximately 140 minutes (2.0° F/min), soak/dwell at temperature for 2 h, and then ramp down to 140° F in approximately 105 min (2.0° F/min). Free-standing post-cure cycles at 425° F for 120 minutes.

Vacuum Feedthroughs: For oven operation, vacuum lines are to be attached to the mold/s approximately every 6’. Considering that up to two molds could be cured side by side, Oven Section 1 shall have a minimum of twelve (12) vacuum feedthrough ports located near the door end. Oven Section 2 shall have a minimum of twenty two (22) vacuum feedthrough ports located near the door end. Vacuum feedthrough ports shall use Airtech International’s AQD 500TF quick disconnect couplings or similar ¼” NTP vacuum fittings. The vacuum hoses inside the oven will terminate in male fittings so the vacuum ports inside the oven shall use female fittings. There is no need to include vacuum hoses and/or vacuum equipment (to be supplied by NASA).

Thermocouple Feedthroughs: For oven operation, thermocouples are to be attached to the mold/s approximately every 6’. The other end will terminate in a male connector. Considering that up to two molds could be cured side by side, Oven Section 1 shall have a jack box with a minimum of fourteen (14) high temperature K-type thermocouple female jacks located near the door end. Oven Section 2 shall have a minimum of twenty four (24) high temperature K-type thermocouple female jacks located near the door end. The jacks shall be hard wired to the data recorders. There is no need to include internal thermocouples for attachment to the mold (to be supplied by NASA).

Temperature recorder: Two separate digital data recorders with a combined total of at least 38 inputs and Ethernet/IP communications. See thermocouple feedthrough requirement above for digital recorder layout required per oven section. One should have at least 14 inputs for Oven Section 1 and the other at least 24 inputs for when Oven Sections 1 and 2 are coupled.

Movable: Oven shall include legs with swivel casters (min. 3” diameter, 2” wide) and swivel locks for ease of transportation around the build. The numbers of legs and casters shall be such that the pressure exerted on the floor by them due to the weight of the oven, part tray and mold is less than 500 psi.

2. SYSTEM OVERALL PHYSICAL DIMENSIONS

Oven Overall System (Including Both Oven Sections) Overall Physical Dimensions:

≤ 678” length.

≤ 62.5” width (does not include side removable mounted control enclosure).

≤ 92” height (does not include recirculation blower, includes potential removable legs).

≤ 120” overall system height including recirculation blowers or heater boxes.

Figure 1 shows the location within the facility where the oven will be placed. Facility constrains dictate the maximum length of the oven and associated rolling cart to be under 111.25’ when axially aligned. The oven width and height external dimensions are sized because the first section of the oven needs to be housed in a room that has a current door opening of 5’10” W x 7’10” H. During integration, any possibly equipment like heater boxes, recirculation blowers, etc. that protrude beyond this oven cross-section dimensions will be added to the first section of the oven once this is placed inside the room using the additional door in the room. That side door is 5’10” W x 8’6” H. The ceiling height in that room is 14’.

A minimum of 4’ clearance is required from the tallest point of the assembled oven including the external components like the heater box/es to the room ceiling for ease of rigging and integration inside the room.

Oven Sections: two (2). Section one (located inside Room 111) shall measure approximately 360” length inside dimension and approximately 372” length outside dimension with the front modular door in place. The exhaust unit shall be positioned outside Room 111 (i.e in Room

127) on the roof of Oven section 1. This first oven section shall be capable of operating alone and thus shall include power/controls/exhaust units.

Oven section 2 (addition) is to be located in Room 127 and shall measure approximately 306” length inside dimension and approximately 318” length outside dimension with the modular front door in place. This section will be removed when the length of the parts to be cured do not require the extended oven configuration.

Oven Inside Heat Zone Dimensions (Both Oven Sections in Place): 666” Length x 30” Width x 27” Height (from top of part tray). The maximum desired cross-sectional area of the mold/part is 24” W x 24” H, allowing a minimum of 3” clearance from the top and side walls.

The clearance from the 654” long molds to the front and back internal walls of the heat chamber shall be 6” to minimize possible edge effects during the curing process of the parts.

Pass Height (Floor to Top of Working Tray): Pass height shall be between 36” and 42” measured from the floor to the top flat surface of the part tray once this is placed inside the oven. The oven system shall include leveling legs with casters and therefore the pass height shall be slightly adjustable to account for any height mismatch between the rolling cart and the oven due to manufacturing tolerances.

Figure 1: Oven integration within the NASA LaRC facility.

3. DETAILED SPECIFICATIONS

Heating: The oven shall include electric heating elements capable of generated a minimum of 100 KW of power between both heated oven sections to achieve a uniform heating and the rates desired required for curing. These heating elements can be part of a large heater box or be distributed throughout the length of the oven and shall be roof mounted.

Recirculation blower: The oven shall include 1 or 2 recirculation blower units with combination airflow rated at a minimum of 12,000 CFM at 15 HP for a single unit of 6,000 CFM at 5 HP for a dual unit. For a single unit configuration, the blower unit power shall be adjustable for operation with the volume of Oven Section 1 alone. The blower unit/s shall be roof mounted after the oven is integrated into Room 111 and Room 127.

Heat Zone insulation: 6” thick insulation is required all around the oven for minimal heat loss and high efficiency, except for the modular door that can be reduced to 4” to comply with overall length requirement. The maximum surface temperature of any exterior wall while the oven is in operation shall be 150° F.

Oven Internal Ductwork: The oven internal ductwork shall be such that the molds/parts get heated from the sides and below using combination airflow with the return recirculation plenum duct above.

Air Exhaust: To include an air exhaust system with a backward inclined exhaust blower with a manual damper. A minimum of 1,500 CFM at 1HP is required. The exhaust unit shall be roof mounted within the first 5” of Oven section 1, i.e. inside Room 127 and outside Room 111.

Make-up Air Unit: The unit/s shall vent directly to the facility, i.e. Room 127. There will be no additional duct to be made in the facility to vent outside through a dedicated facility roof-mounted make-up air unit.

Power Supply/Controls: Fully wired NEMA 12 electrical panel, filtered fan-cool enclosure.

The unit shall have a single door with a programmable controller (1 program and 8 segments at least), a digital recorder with at least 24 inputs and Ethernet/IP communications

Wiring: Oven unit delivered shall be pre-wired.

Structural: Painted steel angle constructed support structure.

Paint: Oven exterior shall be painted dark blue and applied with an airless sprayer. Exact color coat specification will be specified at the time of order.

Oven Loading Front Doors: The oven shall include a modular flanged door section that may be bolted to the front of either oven section. It shall include the 4-6” insulation front wall and 4” insulated dual hinged doors. Doors shall be able to open at least 135 degrees.

Guiding Element for the Part Tray: The oven sections shall include either dual inverted V-groove tracks for V-groove wheels fixed to the bottom of the part tray or integrated wheel tracks for supporting a flat bottom surface part tray (integrated V-groove tracks and dual inverted V-groove tracks fixed to the bottom surface of the part tray is also a possibility). The tracks will provide alignment and aid in the process of manually getting the part tray in and out of the oven. These tracks shall have an approximate spacing of 15-18” and shall not be adjustable. Designs where maintenance is minimized would be preferred.

Facility Power Available: 480VAC/ 3-phase/ 60Hz/ 225A service is available within the facility. There is a spare 3-phase 225 A breaker switch that will be used.

Emergency Stops: Emergency stop buttons shall be placed at each end of the oven system and one placed on the control panel for a total minimum of five (5) E-stops.

4. ADDITIONAL OVEN SAFETY REQUIREMENTS

1) Use noncombustible construction throughout, arrange interior with smooth surfaces to permit easy /complete cleaning, and do not have any inaccessible spaces.

2) Insulate oven floor to the same degree as the oven walls and roof.

3) Manifolding exhaust ducts from other ovens or equipment is not safe nor permitted by code. Therefore, exhaust duct of new oven cannot be connected to adjacent existing oven. The existing exhaust penetration left from an old hood can be re-purposed.

Mechanical engineer will need to design and submit exhaust duct details to NASA for approval. NASA will award the exhaust duct related work to an onsite contractor. Oven vendor shall work with the contractor to guarantee the exhaust system is up to code.

4) Provide cut-off valves on the exterior on each vacuum line to each platen, arranged to be closed manually if vacuum within the plastic vacuum bag is lost.

5) Design oven recirculation and exhaust fans for the maximum possible exhaust temperature (450° F) and be suitable for the material and vapor present.

6) Provide an excess temperature limit control (requiring manual reset) that is independent of any automatic or manual temperature control. Provide an audible/visual alarm and interlock with the source of heat. Ensure the excess temperature limit controller indicates the temperature and is marked with the set point.

7) Adjust the set point of the excess temperature limit control no higher than 50 °F above the oven temperature control set point.

8) Locate sensor for the excess temperature limit control where it will most rapidly detect an excess temperature condition.

9) Interlock the excess temperature limit control with a contactor in the main supply circuit to the heating unit. Do not use the contactor that is used for temperature control.

10) Only use components for the excess temperature control that will fail safe (i.e., cause the same response as an excess temperature condition).

11) Equip oven heaters with a main disconnect device to de-energize all heating circuits in the event a short circuit is not cleared by supplemental branch circuit protection such as circuit breakers. Provide these supplemental devices in accordance with safety, temperature control, and branch circuit requirements.

12) Select electrical devices for controlling the heating load with consideration for the severity of oven service in accordance with Table 1 below. Where the manufacturer’s rating of a device is based on a lighter service than is to be required of it in the oven, such as unenclosed use, intermittent duty, or inductive loads, use a control device having conventional rating higher than that called for by the heating load.

5. LOADING CART/WORK TABLE:

A rolling cart for positioning the work tray in place and loading/unloading it inside the oven is needed. The loading cart will also be used as a work table to do the layups once the part tray is placed on top. The general specifications of the loading cart are:

Dimensions: The total loading cart length shall be made equal to the internal length of the oven minus 6”, i.e. 660”. The maximum width shall be 30”. The overall height shall be chosen considering the requirement of pass height (floor to top of work tray) of the oven aforementioned.

Modular: The loading cart shall be constructed from two independent segments that can be flanged together. The length of each segment shall be made equal to the internal length of each oven section. The 300” section correspondent to Oven Section 1 shall have both ends flanged in case the overall length of the loading cart wants to be increased in the future by adding more segments.

Movable: The loading cart shall be manually manipulated for positioning the work tray in place. It shall include legs with swivel casters and swivel locks that should allow 90 degree turns, such that the cart can move perfectly sideways at an axis normal to its longitudinal axis.

Front and sideways motions will be needed to position the cart. A minimum of three sets of legs per loading cart segment shall be included. Casters with a minimum diameter of 5” are preferred.

Additional Height Constrain: The 300” long loading cart segment has to clear the height of a 29.5” tall and 96” long table that is fixed to the floor of the facility upon axial alignment with the oven. A 90 degree turn of the cart and sideway motion will be required for this maneuver.

Therefore, the minimum height measured from the floor of the lowest element of the loading cart needs to be 30” for a 108” long segment (with 6” of clearance from each side). The start of this 108” long segment shall be located 62” from the front end of the loading cart (furthest section from the oven). The rest of the loading cart does not have this height constrain and can include legs and thicker beams, i.e. first 62” segment and segment after 62” + 108” = 170”.

Structure: The loading cart shall be constructed from carbon steel framework structure with a minimum beam cross-section size of 5” H (8”H preferred) x 3” W.

Flatness: The loading cart shall have a flat top surface to within 1/16” for the flat part tray to rest on.

Guiding Element for the Part Tray: The loading cart shall include either dual inverted V-groove tracks for V-groove wheels fixed to the bottom of the part tray or integrated wheel tracks for supporting a flat bottom surface part tray (integrated V-groove tracks and dual inverted V-groove tracks fixed to the bottom surface of the part tray is also a possibility). The tracks will provide alignment and aid in the process of manually getting the part tray in and out of the oven. These tracks shall have an approximate spacing of 15-18” and shall not be adjustable. Designs where maintenance is minimized would be preferred.

Paint: The loading cart shall be painted dark blue. Exact color coat specification will be specified at the time of order.

6. PART TRAY

A part tray is needed for transferring the molds/parts inside the oven. This tray will be inside the oven during its operations. The part tray will be used as a working surface to place the molds and do the composite layups, and vacuum bagging on. The general specifications of the part tray are:

Dimensions: The total part tray length shall be made equal to the internal length of the oven, i.e. 660”. The maximum width shall be a couple of inches less than the heated zone width, i.e.

28”. The overall height shall be chosen considering the requirement of pass height (floor to top of work tray) of the oven aforementioned and the overall height of the loading cart. The work tray plate thickness shall be 1” at a minimum.

Modular: The part tray shall be constructed from two independent segments that can be flanged together. The length of each segment shall be made equal to the internal length of each oven section. The 300” section correspondent to Oven Section 1 shall have both ends flanged in case the overall length of the part tray wants to be increased in the future by adding more segments.

Temperature: The part tray shall be capable of withstanding without losing structural integrity or producing excessive deformation the maximum temperatures to be experienced inside the oven (450 °F) plus a 50 °F margin, i.e. 500 °F.

Structure: The part tray shall be constructed from a rigid material capable of guaranteeing the structural integrity and flatness of the top surface. An open lattice grid construction is required for air to flow from the bottom of the oven to heat the molds and produce a more uniformly heating profile.

Flatness: The part tray’s top surface shall have a flatness to within 1/16” for the part molds to rest on.

Guiding Element for the Part Tray: The bottom surface of the part tray shall include either two rows of V-groove wheels that will rest on the two V-groove inverted angle tracks of the loading cart and oven, or have two V-groove inverted angle tracks that will rest on the V-groove wheels of the loading cart and oven, or be flat to work with regular wheels. Designs where maintenance is minimized would be preferred.

7. INSTALLATION

NASA will use an on-site contractor to rig the oven system, its associated equipment, rolling cart and part-tray from the flat-bed truck to be used for shipping to the inside of Room 127 and Room 111. NASA will provide the main power source and all external wiring, conduit, and ducting to the system during installation. The vendor shall provide engineers/technicians upon arrival of the oven to the facility to help integrate the oven, commission and start it and train the future NASA operator employees. Installation costs shall be itemized with details of the level of support to be provided, including prospective timeline to complete the tasks.

8. COST BREAKDOWN

Itemized costs shall be provided for each element: oven system, rolling cart, part tray, shipping, installation, start-up & commissioning, etc.

9. WARRANTY

A minimum of 2 year warranty for the oven system and associated equipment shall be required.

In the event that any part or parts, excepting expendable items such as, but not limited to refractories, thermocouples, and similar items, shall fail within the first twenty-four (24) months from date of shipment due to defects in material or workmanship, the vendor shall repair or replace F.O.B. destination, such defective part or parts.

10. Place of Performance The vendor shall deliver to the following address:

NASA Langley Research Center Building 1206 Hampton, VA 23681-2199

11. Period of Performance

Detailed engineering drawings for all the items requested shall be delivered no later than 2 weeks ARO. All of the final products shall be received at NASA Langley no later than 18 weeks after approval of the detailed engineering drawings by NASA.